Attachment limits by service
| Service | Usual limit |
|---|---|
| Gmail | 25 MB in attachments; larger files are sent as a Google Drive link |
| Outlook.com (web) | Around 20–34 MB depending on how you attach; larger files are offered as a OneDrive link |
| Outlook desktop app | 20 MB by default for internet email accounts |
| Work and school email | Often 10 MB, set by the organisation |
| 16 MB as a video; up to 2 GB as a document | |
| Discord | 20 MB free; 50 MB Nitro Basic; 500 MB Nitro |
The hidden overhead: why 25 MB isn’t really 25 MB
Email was designed for text, so attachments are converted to text (Base64 encoding) before sending. That makes them about a third bigger in transit. A 20 MB video becomes roughly 27 MB of email, which can bounce at a server with a 25 MB message limit, especially at the recipient’s end, which you can’t see.
Rule of thumb: for an email that must arrive anywhere, keep video attachments to about 18 MB. For work or school addresses, aim for 7 MB if you suspect a 10 MB limit. Use the custom size in the email compressor to choose exactly.
Three ways to send a large video
1. Compress it to fit
Best when the recipient should be able to watch it straight from the email or chat. Compressing re-encodes the video at a bitrate that fits, usually with little visible change on a phone or laptop.
- Open the email compressor and choose 25 MB, or a custom size such as 18 MB.
- Drop the video in, check the expected quality, and press Compress.
- Attach the saved MP4 to your email.
2. Send a link
Best for long videos or full-quality originals. Upload to Google Drive, OneDrive, Dropbox or iCloud and share a link. Gmail and Outlook do this automatically for big files. Check the link’s sharing settings so the recipient can open it without asking for access.
3. Send as a document in a chat app
WhatsApp and Telegram can send large files as documents, without recompressing them. The recipient downloads the file before watching. See WhatsApp’s video limits.
Which method should you use?
| Situation | Best method |
|---|---|
| Short clip, recipient should just press play | Compress to fit |
| Long video or original quality needed | Cloud link |
| Sending to a phone on WhatsApp | Compress to 16 MB, or send as a document |
| Uploading to a form with a size cap | Compress to the form’s limit |
| Only the audio matters (talk, voice note) | Convert to MP3, which is much smaller |
Mistakes to avoid
- Zipping the video saves almost nothing, because video is already compressed.
- Splitting into many emails is awkward for the recipient; compress or link instead.
- Sending HEVC iPhone videos to Windows users can leave them with a black screen. The email compressor saves H.264 MP4, which plays everywhere.
Telegram, Slack and Teams
Telegram allows very large files (up to 2 GB, or more with Premium), so compression is about speed rather than limits. Slack and Microsoft Teams accept large uploads too, but people watching on phones will thank you for a smaller file. For any chat app, an MP4 of 50 MB or less plays quickly for everyone.
Free toolTry it now: Compress for email Fit a 25 MB attachmentQuestions
What is the largest file I can email with Gmail?
25 MB in attachments. Larger files are sent as a Google Drive link.
Why did my 20 MB attachment bounce?
Attachments grow by about a third in transit, so 20 MB can exceed a 25 MB server limit. Aim for about 18 MB.
How do I send a 1 GB video?
Share a cloud link, or send it as a document on WhatsApp or Telegram.
Will compressing ruin the quality?
For most clips viewed on phones and laptops, the difference is hard to see, especially at 15 MB and above.
Can I email a video from my iPhone?
Yes. Mail Drop and iCloud links handle large files; for a normal attachment, compress it first.