Compress Video for Email (25 MB Limit)
Email caps uploads at Gmail 25 MB, Outlook.com 20 MB, Exchange / work mail 10 MB. VidSmaller compresses any video down to 18 MB so it fits on the first attempt — H.264 MP4 out, no watermark, nothing to install, no account needed to try it. Cloud encoding keeps running if the tab closes. The no-account trial accepts videos up to 3 minutes and 200 MB; paid plans accept files up to 1.5 GB.
Almost every page about emailing a video tells you Gmail’s limit is 25 MB. That is true, and on its own it is not enough to go on: the 25 MB is the whole message after encoding, not the file sitting on your disk.
Drag and drop a video file to start
Checking your file limits…
Supported: mp4, webm, mov, mkv, avi, wmv and 33 formats in all
Email file size limits, and what they really mean
Three different sizes get called “the limit”, and they are not the same number. There is the raw file on your disk — the one you compress to. There is the encoded message: attachments are base64-encoded in transit, which costs about 37% once MIME line breaks are counted, and that is the size the limits are measured against. And there is the individual product’s cap: Gmail personal is 25 MB per message when sending, Outlook.com is 20 MB, and work mail on Exchange often ships a 10 MB default that your administrator may never have raised. We pre-set 18 MB because it clears all three of those on every common send path, not because 18 MB is a published limit anywhere.
| Plan / upload method | Maximum file size |
|---|---|
| Gmail | 25 MB 25 MB is the whole message, measured after base64 encoding (~1.37x the raw file once MIME line breaks count). Gmail on the web does not bounce above it — it swaps the attachment for a Drive link. SMTP clients (Outlook, Thunderbird, Apple Mail) do bounce. ~18 MB raw clears both. |
| Outlook.com | 20 MB |
| Exchange / work mail | 10 MB Microsoft ships a 10 MB default for Exchange accounts. Your administrator may have raised it; you cannot assume they did. |
Limits verified 2026-09-14. Sources: Google — Send attachments with your Gmail message · Microsoft — Reduce attachment size
What 18 MB actually buys you
Every other page tells you the limit and stops there. The limit is the easy half. Here is the half that decides whether your video is watchable: at a 18 MB target, this is exactly how much bitrate is left for each duration, and the largest resolution that bitrate can carry without falling apart.
| Video length | Bitrate left for video | Resolution it carries | Verdict |
|---|---|---|---|
| 30s | 4,805 kbps | 1080p | Looks fine |
| 1 min | 2,338 kbps | 720p | Looks fine |
| 2 min | 1,105 kbps | 480p | Looks fine |
| 5 min | 365 kbps | 360p | Visibly rough |
| 10 min | 119 kbps | — | Visibly rough |
| 30 min | — | — | Not realistic |
Method: the bitrate column is arithmetic — 18 MB spread across the duration, minus 128 kbps for stereo audio and 2% for container overhead. It is a hard ceiling, not an estimate. The resolution and verdict columns are a recommendation, derived from published H.264 bitrate ladders and pulled down about a third, because re-encoding footage that has already been compressed once survives lower bitrates than encoding a clean master does. Deliberately conservative — we would rather under-promise than tell you a video will look fine when it will not.
18 MB across lengths and resolutions
The left column is what you have to spend at each length; the cells are what each resolution needs. Green means you clear it comfortably, amber means it is watchable but soft, and grey means pick a smaller frame. Reading down a column shows how long a clip can get before that resolution stops being worthwhile on email.
Source: Computed, not measured — no encoder was run to produce this figure · Method: 18 MB spread over the duration, minus 128 kbps audio and 2% container overhead. Thresholds come from published H.264 bitrate ladders, reduced by about a third for re-encoded source.
How to compress a video for email
Drop your video in
MP4, MOV, MKV, AVI, WebM and 33 formats in all. Nothing to install — your browser uploads over a one-time link and the file never touches a third party.
The target is already 18 MB
We pre-set it below the hard ceiling on purpose. A target-size encode usually lands within a couple of percent of the number you gave it, but we have measured footage that overshoots by up to a tenth — and landing over a hard limit means the upload fails. Change it if you want a different number.
Download and upload
Encoding runs on our servers, so you can close the tab. The result comes back with no watermark on any plan, in an MP4 that email will accept.
Email compression FAQs
What size video can I attach to an email?
About 18 MB of actual video, if you want it to work everywhere without thinking about it. Gmail’s advertised limit is 25 MB and Outlook.com’s is 20 MB, but those are ceilings on the encoded message, which runs roughly 1.37x the file on your disk. Work email is often the real constraint: Microsoft ships a 10 MB default for Exchange accounts, and plenty of administrators never change it. Your recipient’s server has its own limit too, and you cannot see what it is — which is the actual argument for leaving headroom rather than aiming at the ceiling.
Why did my email bounce when the video was under 25 MB?
Base64 encoding, and which program you sent from. Email cannot carry raw binary, so attachments are re-encoded into text at a cost of about 37%. Your 24 MB video is a 33 MB message, and the limits apply to the message. Where it matters is the send path: Gmail on the web does not bounce — above its limit it quietly pulls the attachment out and inserts a Google Drive link instead. A desktop client sending over SMTP — Outlook, Thunderbird, Apple Mail — makes no such substitution, so that is where you get the rejection, and where the recipient’s own server cap can reject it after you have already sent it. Compress to 18 MB and the encoded message lands around 24.7 MB, inside Gmail and Outlook.com both.
Should I use a Drive or Dropbox link instead?
For anything long, yes — and Gmail will do it for you automatically above 25 MB. But a link is worse for the recipient in real ways: it needs a second click, it can be blocked by corporate security, it expires, and it leaks who opened it and when. For a clip that genuinely fits in 18 MB, an attachment is the better experience.
How long a video fits in 18 MB?
At 720p, comfortably around two minutes. At 1080p, closer to one. Past about five minutes you are into territory where 480p is the honest answer — see the table above for the exact arithmetic at each length. If the recording is a screen capture rather than camera footage, you will do considerably better than these numbers, because screen content compresses far more efficiently than moving scenery.
The reasoning behind these numbers
- Why 25 MB is the wrong target for emailThe size page for the number Gmail documents, and the 37% that makes it fail.
- Post it in Slack instead of attaching itSlack takes 1 GB per file on every plan including Free, which is fifty times what a work mailbox will hold.
- Gmail says 25 MB. It means about 18.Attachments are base64-encoded in transit, so the number on the label is not the number you can send.
- Losing 70% of the file and none of the qualityMost phone recordings carry enough slack to fit an inbox without a visible change.