How to Increase Outlook Attachment Size Limit? Send Large Files

One of the common problems that every other Outlook user faces is the Outlook attachment size limit.

Imagine you are composing a last-minute important work email in Outlook, attaching that crucial sales deck, and then… boom! The dreaded “Attachment size exceeds the limit” message pops into your screen. 

It’s frustrating, right? 

This blog post will show you ways to increase your Outlook attachment size limit and have an uninterrupted workflow.

First, let’s start with understanding the current Outlook attachment size limits and why they exist

The attachment size limit for Outlook varies depending on the type of account. 

For Internet email accounts such as or Gmail, the combined file size limit is 20 megabytes (MB). 

For Exchange accounts (business email), the default combined file size limit is 10 MB. 

However, if you’re using the Outlook email client with a Microsoft 365 subscription, the limit increases to 150 MB.

Please note that these limits can vary and it’s always a good idea to check the specific provider’s guidelines for the most accurate information. Using Microsoft 365 services can significantly streamline your workflow and enhance your ability to share larger files, ensuring your communications remain efficient and effective.

Learn more: Exchange Online Limits

Email servers have their storage capacities, and hefty attachments can quickly fill them up. 

Outlook sets a default attachment size limit of 20MB to ensure smooth operation and prevent overloaded servers. This attachment limit is in effect for Outlook 2019, Outlook 2021, Outlook for Microsoft 365, and Outlook on the web.

While this helps maintain server efficiency, it can be a major pain point for those of us dealing with larger files like presentations, videos, or complex spreadsheets.

Now that we have a clear understanding of the what and why, let’s tackle ways of increasing Outlook attachment size limits.

Here is a tried and tested way to maximize your Outreach email attachment size limit for email outreach. 

Increase Outlook attachment size limit for desktops using ‘Registry Path’ for Windows

Regardless of the Exchange Server version in use (2016, 2019, 2022, or Exchange Online), your Outlook data remains accessible. 

While the primary storage is on the server, Outlook maintains local copies in .pst or .ost files for offline access and convenience on your computer. 

By increasing the .pts and .ost file size limit, your Outlook attachment size limit for desktop can go up to 95 GB. 

Follow these steps to maximize Outlook email attachment size limit:

📌Step 1) Press the Windows + R key and type “regedit” to open the registry editor on Windows.

📌Step 2) Find the entry based on your version of Outlook.

  • Outlook 2007  HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Preferences
  • Outlook 2010 HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences
  • Outlook 2013 HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\\Preferences
  • Outlook 2016 and 2019 HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\\Preferences
Microsoft registry editor - for increasing outlook attachment size limit

📌Step 3) Find the maximum attachment size and put your preferred attachment size limit. Put the ‘base’ option as desired. 

📌Step 4) Close the registry and reopen Outlook to send larger files.

Additionally, you may refer to this official Microsoft resource for your guide(web app).

If you need help with the SMTP setup for Outlook, take a look at Outlook SMTP Settings | Complete Guide

Here are some easy ways to send large files using Outlook without thinking about the Outlook attachment size limits. 

It’s the best way to send files on Outlook without having to worry about the file size limit. 

This method is useful because the recipient receives the files without a compromise in the size or quality of the files. In most cases, the recipient can open the file without having to download the file.

For free and paid cloud storage, you may use cloud storage services such as Google Drive, Microsoft Onedrive, Dropbox, iCloud, etc. 

Simply upload your file on the cloud storage you use ➡️make changes to the accessibility of the file ➡️ copy its link ➡️Attach the link to your email.

It’s a great fix to the Outlook attachment size limit issue. Compressing your files will reduce the quality as well as the size. But don’t worry if it’s a Doc or an Image of high resolution. 

You can use an Outlook Add-in such as Weight Diet for Outlook file attachment optimization.

There are multiple free tools available on the internet for compressing different files such as documents, images, videos, interactive flip books, etc. 

For example, you may use the tool Optimizilla for image compression of different formats.

Sometimes it may happen that even after compressing files, the size limit exceeds 20 MB. That is when this trick comes in handy. 

Use a tool such as 7-Zip and WinRaR to split large large-sized files into comparatively smaller-sized files. 7-zip compresses large-sized files into 7 MB.

Although this technique works, it’s not recommended. Firstly, splitting large-sized files can be daunting and time-consuming. Second and finally, it can alter the quality of the file.  

Not everyone likes seeing attachments in their email. So the best possible way is to avoid using them whenever you can. 

Do not use attachments or links for the first email of your sequence. The idea is for the first email of your sequence to reach the prospect’s primary inbox.

If this happens then the rest of the email sequence thread (with or without attachments) will automatically reach the primary inbox

Here are 3 tips for smooth collaboration despite Outlook email attachment size restrictions:

Use features like OneNote or SharePoint to share and co-edit documents in real time without relying on email attachments.

If your organization allows, leverage secure shared drives or secured file-sharing platforms like Microsoft Onedrive, and Google Drive to facilitate collaborative access to large files.

Embrace a digital platform mindset. Tools like online collaboration platforms or project management software can foster seamless collaboration while minimizing reliance on email attachments.

The 20MB Outlook attachment size limit isn’t a hard and fast rule; it’s a sensible starting point.

Using the tricks and tips mentioned above, you can hack away Outlook attachment size limits to share information efficiently on email.

Remember, while expanding Outreach attachment size limits offers greater flexibility, responsible file sharing is key. Think about your recipient’s bandwidth and capabilities before hitting “Send.”

For automating your cold email outreach, use SmartReach, a leading Sales Engagement Platform, loved and trusted by over 3000 businesses all over the world. 

Book a demo today to give your sales process the boost it deserves! 

  1. What is the attachment size limit for Outlook?

The attachment size limit for Outlook is 20MB. 

  1. What is the Outlook attachment size limit?

The Outlook attachment size limit is up to 20 MB.

  1. How to increase the Outlook attachment size limit on Mac?

Unfortunately, there is no way to increase the Outlook size limit on Mac. Users are advised to compress or send their files through a cloud storage service to maximize the Outlook email attachment size.

  1. How do I send a 50 MB file in Outlook?

To send a 50 MB file in Outlook, one needs to compress the file either to reduce the file size or send the 50 MB file via cloud storage such as Onedrive, Google Drive, etc. 

  1. What is the file size limit for email?

The file size limit for each email platform differs; for Gmail, the attachment size limit is 25 MB, for Outlook the email attachment size limit is up to 20 MB, and for Zoho mail, it’s up to 20 MB, and for Yahoo mail, it’s 25 MB.

  1. Can I increase the Outlook attachment size limit for Android and Apple mobiles?

No, there is currently no option to increase the Outlook attachment size limit for mobiles, including Android and Apple.

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