How to Increase Outlook Attachment Size Limit

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What is Outlook’s Default Attachment Size Limit?

If you’re a frequent Outlook user, you’ve probably encountered the dreaded “attachment size exceeds allowable limit” error when trying to email large files. While frustrating, this limit exists for good reason. Outlook restricts attachment sizes to prevent overloading mail servers and accommodate the restrictions of recipient providers.

So what exactly is Outlook’s default limit for email attachments? Let’s take a closer look.

The 20MB File Size Restriction for Outlook Email Attachments

The standard attachment size limit across all versions of Outlook for Windows is 20MB per email sent. This applies to Outlook 2019, 2016, 2013, 2010 and 2007.

For Outlook on the web (previously known as and Outlook mobile apps, the limit is also 20MB.

This 20MB limit includes the total size of all file attachments added to a single outgoing email message. Even if you attach multiple files, their combined size cannot exceed 20MB or the email will fail to send.

Important Exceptions:

  • For Outlook accounts connected to Microsoft Exchange Server, the default limit is set lower at 10MB per email.
  • Paid Outlook 365 subscriptions through Microsoft 365 plans come with a more generous 50MB attachment limit.

So in summary, the standard 20MB restriction applies to:

  • Outlook desktop app for Windows
  • Outlook mobile for iOS and Android
  • Outlook on the web (

With exceptions for Exchange and paid Office 365 accounts allowing 10MB and 50MB respectively.

Limits Apply to Single and Multiple File Attachments

The 20MB size limit applies whether you attach a single large file or multiple smaller files. The total of all attachments cannot exceed 20MB.

For example, you could attach:

  • 1 file up to 20MB
  • 2 files up to 10MB each
  • 5 files up to 4MB each

But if the total exceeds 20MB, Outlook will block sending the email.

This limit can be frustrating if you need to share things like large presentations, videos, CAD files, or photo albums with clients and colleagues.

Fortunately, there are some workarounds covered later in this guide.

Difference Between and Exchange Accounts

It’s important to note the distinction between and Exchange mailbox accounts. is the free, personal email service from Microsoft. If you have an,, or email address, you are using

Exchange mailboxes are business, school, or organization accounts hosted on Microsoft Exchange Server. These usually have email addresses ending in your company or organization’s domain rather than

The key difference is that Exchange accounts have a 10MB attachment limit by default rather than 20MB. Exchange administrators can increase this limit, but 10MB is the out-of-the-box setting.

However, both and Exchange accounts use the same Outlook desktop and mobile apps. So it’s easy to confuse the 20MB “standard” limit with the 10MB Exchange default.

When in doubt, check with your IT team about the specific attachment size limit applied to your business Outlook mailbox.

Now that we’ve covered the basics of Outlook’s restrictive attachment limits, let’s explore why these limits exist in the first place.

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Why Does Outlook Limit Attachment Size?

As we saw in the previous section, Outlook desktop and web mail impose relatively low default attachment size limits of 20MB per email sent.

For those needing to share larger files up to several GB, this small allowance can feel arbitrary and restrictive.

But there are some technical and practical reasons behind Outlook capping attachment sizes. Let’s explore what’s behind these limits.

Preventing Large Attachments Overloading Mail Servers

The primary motivation for limiting attachment size is preventing massive files from degrading mail server performance.

A single oversized 10GB video attachment might not doom a modern enterprise-grade email system. But allowing Outlook’s tens of millions of users to upload huge files could definitely overwhelm servers.

Some specific ways giant attachments can impair mail servers:

  • Network bandwidth congestion – Big uploads consume more of the available connections to the server, slowing transfers for other users. Think rush hour traffic.
  • Storage capacity filling up – Enough giant attachments will eventually eat through finite server disk space.
  • Processor load spiking – Large uploads require more memory and CPU cycles to handle, reducing responsiveness.

Outlook’s 20MB limit provides a reasonable ceiling to guard against these issues. It strikes a balance between user convenience and protecting shared resources.

Of course, a 20MB PowerPoint presentation is trivial for modern infrastructure to handle. But the limit remains in place as a safeguard against potential performance degradation if every user started uploading multiple 1GB files.

For business class mail systems, administrators can adjust attachment thresholds as needed based on real-world capabilities and consumption patterns.

But for high-volume public services like, a conservative default size goes a long way towards ensuring stability.

Attachment Size Restrictions in Public Cloud Mail

To understand Outlook’s rationale, consider the scale of their email operations:

  • 400 million+ active users
  • Billions of emails sent and received per day
  • Exabytes (EB) of storage across datacenters

At this massive scale, small individual allowances add up. Just 1,000 users attaching 10GB files could fill a 1TB disk.

A prudent attachment size limit prevents capacity from being consumed by a tiny fraction of heavy users.

Of course, Microsoft engineers continuously expand capacity to handle growing demand. But limiting attachment sizes is a simple lever to help ensure overall mail reliability.

In a way, it’s similar to the concept of speed limits on highways. Even modern 8-lane superhighways could safely accommodate faster speeds for most drivers. But modest limits help optimize safe traffic flow for all vehicles.

Outlook’s attachment restrictions aim to maintain a smooth flow for the billions of emails traversing servers each day.

Accommodating Recipient Email Provider Limits

Outlook’s attachment size limits also account for restrictions imposed by recipient mail services.

For example, here are the maximum incoming attachment sizes for some popular email providers:

  • Gmail – 25MB per attachment
  • Yahoo – 25MB total per email
  • iCloud – 20MB per attachment

If Outlook allowed attaching a 50MB file by default, many recipients on other services wouldn’t receive it. Their email provider would block delivery of attachments over their limit.

By capping attachments at 20MB, Outlook minimizes recipient delivery failures when exchanging mail cross-platform.

Of course, just because Gmail supports 25MB attachments doesn’t mean users want massive unsolicited downloads clogging their inbox. There’s an implicit etiquette around attachment size.

But the technical limits are there to maintain manageable loads on public cloud infrastructure supporting millions of accounts.

Striking a Balance on Attachment Size

In essence, Outlook’s limit strikes a balance between:

Functionality – Allowing users to exchange meaningful attachments

Constraints – Playing nice with other major email providers

Resources – Not overloading servers and networks

Is 20MB the perfect magic number? Probably not. But it provides a reasonable ceiling based on practical factors both technical and social.

Raising the limit would increase user flexibility but also infrastructure load and oversized deliveries to unwanting recipients. There are always trade-offs around where to set size restrictions.

For power users with specialized needs, workarounds like compression and cloud links provide ways to exchange large files beyond the default constraints.

But for the majority of use cases, Outlook’s 20MB attachment allowance hits a sensible balance between utility and responsibility. It largely prevents mainstream email operations from grinding to a halt.

The core motivations for attachment size limits boil down to:

  • Smooth traffic flow for mail servers
  • Accommodating third-party mail services
  • Avoiding exhausting recipients

These caps solve macro problems by placing modest restrictions on individual users. But as we’ll see next, there are easy workarounds for times when you genuinely need to share oversized files.

In summary, Outlook’s tight attachment limits are designed to:

  • Maintain shared mail server performance
  • Play nicely with other major email providers
  • Avoid exhausting recipients with massive downloads

The roadblock many Outlook users face is how to share large or high-resolution files without bumping up against restrictive attachment limits.

Let’s explore some techniques and workarounds, but before we do that, let’s understand about Encodings in Emails.

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How Encoding Affects Size Limits

In the previous sections, we looked at Outlook’s standard 20MB attachment limit and why it exists.

But there’s an additional factor that makes the real size allowance lower than the stated 20MB ceiling.

Email attachments must be encoded before transmission. This encoding process increases their size, reducing the actual usable space below 20MB.

Let’s take a quick look at how attachment encoding impacts Outlook’s size limits in practice.

Attachments Converted to Email-Friendly Formats

To send a file as an email attachment, its binary data needs to be converted into a text-based format suited for transmission through mail servers.

The encoding process packages file contents into a plain text wrapper that can safely traverse email infrastructure without corruption.

The most common email encoding schemes are:

  • Base64 – Translates binary data to plain ASCII text
  • UUEncode – Similar to Base64 but less efficient
  • BinHex – Encoding method used on old Mac systems
  • Quoted-Printable – Designed for text with some binary like embedded images

Without diving too deep into the technical details, the key point is that attachments cannot be sent in their raw binary form. The file data requires text-based encoding to survive as an email attachment.

Outlook and all major mail clients automatically handle this encoding behind the scenes when you attach a file and hit send. There’s no extra work required on the user side.

But the encoding process does increase attachment file size. And the overhead bites into the maximum size limit imposed by Outlook.

Encoding Increases File Size By Up To 33%

Encoding schemes like Base64 convert each binary byte of file data into a text representation that requires at least 8 bits (a full byte) to store.

In the translation from dense binary to verbose text encoding, the file gains extra bulk, inflated by up to ~33% of its original size.

For example:

  • 10MB PowerPoint file
  • Base64 encoding (33% increase)
  • Now ~13MB encoded attachment

So right off the bat, a 10MB attachment will have grown to 13MB after required encoding, consuming most of the 20MB Outlook limit.

The exact size increase depends on the file’s original binary contents. But in general, expect a 33% size bump to stay conservative.

This encoding penalty means Outlook’s real attachment limit is more like 15MB rather than the stated 20MB. The other 5MB is reserved for mandatory encoding overhead.

Real Limit Lower Than Stated Due to Encoding

In practice, once you factor in enlargement from converting attachments to mail-friendly formats, the usable attachment space is around 15MB per email, not the full 20MB.

The extra 33% should be reserved as a buffer area to accommodate the encoding process and prevent mail delivery failures.

So if you’re right up against Outlook’s limit with a 20MB attachment, there’s a good chance it will fail with an oversized error due to ballooning from encoding. Stay under 15MB to have a safe cushion.

In summary:

  • Encoding increases attachment size
  • Add ~33% for overhead to be safe
  • Real limit is around 15MB, not full 20MB

Understanding this hidden file size penalty can help avoid frustrating instances where a 19MB attachment breaks the 20MB limit after encoding. Leaving spare room in the size budget helps ensure successful delivery.

The next time you get an oversized attachment error from Outlook, try shaving a few MB off the file’s size before reattaching below 15MB for better luck sending it through

Summary on Attachment Encoding

  • Binary attachments encoded to text format for email
  • Encoding schemes like Base64 inflate files ~33%
  • Real usable limit around 15MB once encoding overhead applied
  • Leave spare room under 20MB stated limit to accommodate bloat
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Ways to Send Large Files Beyond the Limit

Now that we understand Outlook’s restricted attachment size limit and why it exists, let’s explore some techniques for working around it.

While the 20MB cap is reasonable for everyday use, power users occasionally need to share large documents, videos, images, or other oversized files.

Thankfully there are several workaround options:

  • Compress files to shrink them under 20MB
  • Split large files into smaller chunks
  • Use file hosting services and share access links
  • Modify registry settings to raise or remove the cap

The best approaches depend on your specific needs and technical skills. Let’s look at pros, cons and steps for each method.

Compressing Large Files to Reduce Size

One easy way to sneak big files through Outlook is compressing them into a smaller package.

Common compression formats like ZIP shrink the file by around 20-30%, which could potentially squeeze it under the 20MB limit.

Built-in Windows Compression

On Windows 10 and 11:

  • Right click the file you want to attach
  • Select Compress from the context menu
  • A compressed ZIP folder containing the file will be created

As long as the ZIP stays under 20MB, Outlook will allow attaching and emailing it through.

Then your recipient needs to extract the ZIP folder to access the original uncompressed contents.

Third-Party Compression Tools

For greater size reduction, install a dedicated compression tool like 7-Zip.

The more optimized compression in 7-Zip can shrink files beyond what Windows natively provides.

There are also Outlook-specific add-ins to automate compression:

  • Weight Diet – Automatically zips attachments to enforced size limits
  • Mail Disabler – Option to compress all attachments

Remember to balance compression level with retaining quality. Higher compression risks corrupting images, videos and other file types.

But for documents and basic business files, compression works well to minimize size and maximize chances of delivery.

When Compression Falls Short

One limitation is that compression ratios vary widely. An Excel sheet may shrink 90%, but an already-compressed JPG might only budge 2%.

If compression still leaves your attachment over 20MB, stronger methods like splitting may be needed.

Overall, compression is quick, free and ideal for modest size reductions to slip just under Outlook’s cap. But other approaches can tackle more drastic file shrinkage requirements.

Splitting Large Files Into Smaller Pieces

When compression leaves attachments too large, a more heavy duty option is splitting the file into multiple smaller chunks under 20MB each.

This approach allows sending all the chunks as separate attachments, while giving the recipient instructions to reassemble them into the original file.

Use file compression/archiving tools like 7-Zip:

  1. Archive the large file using 7-Zip
  2. In 7-Zip, choose Split To Volumes
  3. Specify chunk sizes under 20MB each
  4. Compress each chunk to maximize size reduction
  5. Attach the split volumes to your Outlook email

Your recipient needs to:

  1. Save all the attachment chunks from Outlook
  2. Open 7-Zip
  3. Select Combine Files
  4. Reconstruct the full original file

Downsides of Splitting Files

While splitting large files works, it has some downsides:

  • Complex process for both parties
  • Risk of corrupting file contents
  • Possible data loss if a chunk goes missing
  • Significant recipient workload to reassemble

Because of these potential pitfalls, cloud sharing links have largely replaced splitting files as the preferred Outlook attachment workaround.

Using File Sharing Sites and Links

To avoid attachment size limits entirely, the easiest method is uploading large files to cloud storage, then sharing access links in Outlook.

Popular file sharing platforms:

  • OneDrive – 15GB free with
  • Google Drive – 15GB free
  • Dropbox – 2GB free storage
  • Box – 10GB free

Uploading and Sharing Steps

  1. Upload the large file(s) to your preferred cloud service
  2. Obtain a shareable link to access the file
  3. Paste that link into your Outlook email message
  4. Recipient clicks the link to download the file from cloud storage

Advantages of Cloud Sharing Links

This link-based workaround offers several benefits:

  • Files remain intact – No compression or splitting needed
  • Simple for recipients – Just click and download
  • Better security – Optional password protection and access expiration
  • No real size limits – Cloud services support files up to 1TB+

The only potential catch is cloud storage pricing for high volumes. But free tiers are ample for personal and generic business usage.

For corporations, linking to SharePoint or network shares also avoids local Outlook attachment limits.

Cloud sharing links provide the easiest, most foolproof method for sidestepping Outlook’s attachment constraints.

Increasing Limits By Editing Registry (Advanced)

The most direct way to raise or eliminate size restrictions is editing Outlook’s registry settings. But this is only recommended for technically adept users.

Caution: Modifying the registry incorrectly can severely damage Windows. Backup the registry before making changes.

Here are the general steps for different Outlook versions:

Outlook 2007

  1. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Preferences
  2. Create/modify DWORD value MaximumAttachmentSize
  3. Set to desired max size in KB (e.g. 20971520 KB = 20MB)

Outlook 2010

  1. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences
  2. Create/modify DWORD value MaximumAttachmentSize
  3. Set to desired max size in KB

Outlook 2013 and 2016

  1. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Preferences
  2. Create/modify DWORD value MaximumAttachmentSize
  3. Set to max size in KB or 0 to remove limit entirely

After saving registry changes, restart Outlook for new limits to apply.

Caution When Editing Registry

We strongly emphasized caution here because incorrectly editing the registry can severely break Windows. Corrupting seemingly unrelated keys can crash the entire operating system.

For novice users, compression and cloud links are vastly safer options.

Only attempt registry tweaks if you are an experienced Windows administrator with backups in place. The risks generally outweigh the benefits for everyday users without technical expertise.

Recommended Approaches For Different Users

Now that we’ve covered a range of methods for sending large Outlook attachments, which options make most sense for which users?

Novice Users

  • Use cloud storage links – Safest and easiest workaround
  • Built-in Windows compression – If files just slightly over 20MB limit

Average Users

  • Cloud links – Simplest option for large files
  • 7-Zip compression – More size reduction than built-in tools

Power Users

  • 7-Zip splitting – Safely split files if clouds don’t suffice
  • Registry editing – Eliminate limits but high risks involved


  • SharePoint – Link to internal corporate SharePoint docs
  • Mail server adjustments – Rackspace to raise limits based on infrastructure

The best approach depends on your technical proficiency and specific size requirements. Evaluate options to choose the optimal balance of functionality and simplicity for your needs.

Summarizing options for reducing size

The most practical methods for sending large Outlook attachments include:

  • Compressing files to squeeze under default limits
  • Splitting files into under-20MB chunks
  • Uploading to cloud storage and sharing links
  • Raising or removing caps by editing registry (advanced)

For everyday users, compression and cloud links offer the best tradeoff of convenience and safety. Avoid registry edits unless you are an expert.

If you found these tips helpful, some suggested next steps include:

  • Trialling a cloud service to find your preferred platform
  • Practicing compressing and sharing sample files
  • Researching Outlook add-ins that automate compression/splitting
  • Backing up registry before attempting modifications (experts only)

With the right approach tailored to your abilities, you can easily circumvent default Outlook attachment restrictions to share files of any size.

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Limits When Using Outlook on Mobile Devices

So far we’ve focused on increasing limits and sharing large attachments using the Outlook desktop app on Windows PCs.

But what about attaching files from Outlook’s mobile apps for Android and iOS? Do the same 20MB restrictions apply?

Unfortunately, working around size caps requires more effort on mobile since you don’t have direct access to the registry hacks possible on desktop.

Let’s look at the hurdles and options for attaching large files from Outlook’s smartphone and tablet apps.

No Way to Increase Limits on iOS/Android Outlook

The 20MB attachment limit applies universally across Outlook, including:

  • Outlook on the web (
  • Outlook mobile for Android
  • Outlook mobile for iPhone/iPad

Unlike the desktop app, mobile Outlook does not allow tweaking registry settings to adjust size caps.

The registry edits covered earlier require access to Windows itself, where the registry is stored. iOS and Android do not have an equivalent central configuration database to modify.

The only way around mobile Outlook limits is using cloud storage links.

While desktop Outlook supports more advanced methods like file compression and splitting, cloud links become mandatory when attaching files from iOS or Android devices.

Must Change Registry Settings on Windows PC

To raise or remove Outlook’s size limit when using mobile apps, you need to:

  1. Change registry settings on your Windows PC
  2. Sync that updated Outlook config to your mobile devices

Here’s an overview:

  1. On your Windows PC, edit the registry to increase attachment size caps as covered earlier.
  2. Open Outlook desktop app and sync to apply new registry settings.
  3. On your iOS or Android mobile device, use Outlook’s Sync command to pull down the updated attachment limit from your PC.

Once your increased size allowance syncs from desktop Outlook, the mobile apps will honor the new higher or removed limit.

But again, this requires first modifying the registry on a Windows machine since iOS/Android do not provide direct access themselves.

Can Upload To Cloud Storage and Share Mobile Link

Given the indirect steps required to raise limits on mobile, the easiest and most reliable workaround is cloud storage links.

The process sending large attachments from iOS or Android Outlook is:

  1. Upload the file from your phone to cloud storage
  2. Tap the share link for the file
  3. Paste that link into your Outlook email

All major cloud platforms like OneDrive and Google Drive have mobile apps that allow uploading files from your device’s storage.

This cloud link approach sidesteps Outlook’s capped attachment limit, providing an easy workflow from mobile.

The only limitation is needing a strong internet connection and sufficient cloud storage space. But free tiers are ample for general use.

So in summary:

  • Can’t modify limits directly on mobile Outlook
  • Must sync registry changes from Windows PC
  • Cloud links remain easiest workaround

Mobile adds an extra hurdle to increasing limits, making cloud storage mandatory for large attachments. But desktop tweaks can sync to mobile once registry is modified.

Hopefully these tips help you attach oversized files seamlessly from Outlook on both desktop and mobile!

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How Other Email Providers Handle Size Limits

Throughout this guide, we’ve focused on Outlook’s default 20MB attachment limit and how to work around it.

But how does Outlook compare to attachment allowances in other popular email services like Gmail, Yahoo, and iCloud?

Let’s take a quick look at how other providers accommodate large file attachments.

Gmail Allows 25MB Attachments Per Email

Outlook’s chief competitor Gmail enforces a slightly more generous 25MB limit for attachments sent through Gmail.

So if you’re emailing big files between Gmail accounts, you have an extra 5MB of breathing room compared to Outlook.

Here are the key Gmail attachment size limits:

  • 25MB per individual attachment
  • No specified total limit across attachments

So you could theoretically include multiple 25MB files as long as each one remains under 25MB.

Gmail also displays warning if attachments are approaching the cutoff, whereas Outlook hard stops sending at 20MB.

Overall, Gmail gives a bit more leeway for large attachments, though still caps the size.

Yahoo Mail Sets 25MB Combined Attachment Limit

Yahoo Mail matches Gmail’s 25MB per attachment, but uniquely sets a 25MB total limit if including multiple files.

So if you attached three files at 10MB, 15MB, and 5MB, Yahoo would block sending the email since the combined total hits 25MB.

Here are Yahoo’s stated attachment restrictions:

  • 25MB limit per individual attachment
  • 25MB total for all attachments combined

So Yahoo could allow a 25MB attachment, but accompanying files would then be capped smaller to stay under 25MB total.

Outlook and Gmail check size only on a per-attachment basis.

File Size Allowances Vary By Email Provider

In summary, attachment size limits include:

  • Outlook – 20MB per attachment
  • Gmail – 25MB per attachment
  • Yahoo – 25MB individual/total

Apple’s iCloud Mail sets a 20MB per attachment limit matching Outlook.

Most other providers fall somewhere between 10-35MB per email. Corporate Exchange servers often have very conservative 10MB defaults.

The key takeaway is that attachment allowances vary widely by provider. Outlook is toward the lower end at 20MB, but not the smallest allowance out there.

If managing mixed environments, always check specific attachment limits for each service you integrate. Don’t assume uniform sizing across email platforms.

And when sending large files, lean towards services with higher size caps like Gmail to avoid headaches.

Outlook Limit Considerations By User Base

Another nuance is that certain user bases gravitate towards specific email platforms.

For example:

  • Corporations often standardized on Outlook
  • Consumers frequently use webmail like Gmail and Yahoo

This means if emailing big files across user segments, be mindful of likely provider differences.

What may squeak by under a personal Gmail account’s 25MB allowance might bust a corporate Outlook mailbox capped at 10-20MB.

Once again, know your audience and check respective attachment limits when emailing near any provider’s cutoff threshold.

Summarizing on Varying Email Size Caps

To recap:

  • Attachment allowances differ significantly across email platforms
  • Outlook on the lower end at 20MB vs Gmail/Yahoo 25MB
  • Corporate Exchange commonly limited to 10-15MB range
  • Verify respective limits when emailing cross-platform
  • Favor higher-cap services like Gmail when attaching large files

Understanding these variations can prevent headaches when sharing big files across different email user bases.

What’s been your experience with attachment size limits on other platforms like Gmail or Yahoo? Storage Quotas and Limits

In addition to restrictions on email attachment sizes, mailboxes come with finite storage quotas that cap the total space for your account.

Understanding these cumulative mailbox limits can help avoid hitting capacity when sending and receiving large volumes of email.

Let’s look at the default quotas and how attachment behavior factors in.

15GB Default Email Storage Quota

The free service provides 15GB of storage for each email account.

This 15GB quota covers:

  • Entire email inbox
  • Sent mail folder
  • Deleted items
  • Any other custom mail folders

The 15GB is allocated specifically to email storage. It’s separate from any OneDrive cloud storage associated with the same Microsoft account.

Within the 15GB, there are no specific limits on:

  • Number of messages
  • Number of attachments
  • Size of individual attachments

The cumulative size of everything in the mailbox cannot exceed 15GB.

For moderate personal email volumes, 15GB is ample free space. But business use may require paying to expand the quota.

Shared Pool for OneDrive,, Office 365

While provides 15GB of dedicated email storage, that’s not the end of your free allotment. is part of a Microsoft ecosystem that shares storage quotas across services including:

  • Email (
  • Cloud storage (OneDrive)
  • Office apps (Word, Excel, etc.)

Specifically, OneDrive and share a pool of storage including:

  • 15GB mailbox
  • 5GB OneDrive cloud storage
  • Office app usage also deducts from this pool

So you essentially get 15GB for email, plus 5GB for OneDrive cloud docs that can overlap.

Again, this is ample free space for personal and light business usage. But paying to expand may be required for enterprise-grade volumes.

50GB for Paid Microsoft 365 Subscribers

For those using paid Microsoft 365 (formerly Office 365) plans for business productivity, more generous quotas apply:

  • 50GB mailbox storage
  • 1TB OneDrive cloud storage
  • Full Office app access

With Microsoft 365 subscriptions, the 50GB email allowance plus 1TB of OneDrive provide enterprise-class capacity for companies and teams.

The exact quotas depend on the Microsoft 365 license purchased. But most plans include a major boost over the basic 15GB free tier.

In summary:

  • 15GB default total storage for and OneDrive
  • Shared pool also covers Office apps
  • Microsoft 365 plans include 50GB+ email and 1TB+ OneDrive

Make sure to factor cumulative mailbox size into your attachment size limit workarounds. Even if you can send large files, your total storage quota is finite.

Hopefully these notes help provide full context on’s storage behavior and capacity limits!

Key Takeaways on Outlook Attachment Size Limits

We’ve covered a lot of ground detailing Outlook’s restricted attachment size limits, why they exist, and how to work around them.

Let’s recap the core points to remember:

20MB Per Email Standard Outlook Attachment Limit

The default attachment limit across all Outlook versions is 20MB per email sent. This applies to both individual and combined files added to a message.

Exceptions are Exchange/Office 365 accounts, which may have custom limits from 10-50MB set by administrators. But 20MB remains the baseline.

This relatively low ceiling prevents overloading mail servers and accommodates recipient restrictions. But it hampers sharing large documents and media.

Increase Limit Via Registry Edits (Advanced)

Technically adept users can edit the Windows registry to raise or eliminate size caps in Outlook desktop.

But this is advanced functionality with serious risks if done incorrectly. Most users should avoid registry modifications.

Split, Compress, or Use Cloud Storage as Workarounds

For everyday working around size limits, the best options are:

  • Splitting large files into under-20MB chunks
  • Compressing attachments to reduce size
  • Using cloud storage links for easy sharing

Compression and cloud links offer the simplest, most reliable workarounds accessible to any user.

Evaluate Options Based on Your Needs

Light email users may never run into limits. But power users should:

  • Review specific mailbox attachment limits
  • Test compression tools to find the optimal balance
  • Set up free cloud accounts for easy large file sharing

With the right solution tailored to your use case, Outlook’s pesky attachment restrictions can be overcome with just a bit of effort.

The key is understanding the constraints and why they exist, then choosing a suitable workaround based on your technical skills.

Hopefully these Outlook attachment size limit takeaways provide a solid base for navigating limits and boundaries when sharing files via email. Let me know if you have any other questions!