Compress a video to 25 MB
Twenty-five megabytes is the Gmail attachment limit, and it is the size target where a detail of how email works can make a file that should fit bounce anyway. Here is the arithmetic, including the part most guides leave out.
Drop your video here
or click to browse — MP4, MKV, MOV, WebM, AVI and more
The compressor above is already set to a 25 MB ceiling. It solves the bitrate from the length of your clip, encodes on your own CPU, weighs what came out, and runs again at a corrected bitrate if the first pass missed 25 MB. Nothing is uploaded.
The 25 MB email limit, and the 33% nobody mentions
Gmail allows attachments up to 25 MB; above that it offers to send a Google Drive link instead. Outlook.com sits lower, around 20 MB, and corporate Exchange or Microsoft 365 servers are configured per-organisation and are frequently tighter still.
Here is the part that catches people out. Email cannot carry raw binary, so attachments are base64-encoded in transit, which inflates them by roughly one third. A 24 MB video becomes about 32 MB of encoded message data. Gmail accounts for this on its own sending side, so a 24 MB file will leave your outbox — but many receiving mail servers apply their size cap to the encoded message, not to the original file. That is why an attachment can sail out of Gmail and bounce on arrival.
The practical conclusion: if the recipient is on Gmail, 24 MB is fine. If you do not know what the recipient is on, target 18–20 MB and stop worrying about it.
What fits in 25 MB
Twenty-five megabytes is a comfortable budget for the kind of clip that usually gets emailed: a couple of minutes of screen recording, a short demo, a product walkthrough. The table shows the video bitrate available at each length.
| Clip length | Video bitrate budget | Realistic resolution |
|---|---|---|
| 15 seconds | 13,293 kbps | 1080p or original |
| 30 seconds | 6,582 kbps | 1080p or original |
| 1 minute | 3,227 kbps | 1080p |
| 2 minutes | 1,549 kbps | 720p |
| 5 minutes | 575 kbps | 480p |
| 10 minutes | 271 kbps | 360p |
| 30 minutes | — | Not viable |
Work the same arithmetic for any size with the video file size calculator.
Screen recordings compress far better than this table suggests
The bitrates above are conservative because they have to work for arbitrary footage. Most emailed video is not arbitrary footage — it is a screen recording, a slide deck with a voice-over, or a person talking to a webcam. All three are exceptionally easy to compress, because most of the frame is identical from one moment to the next and the encoder can describe a whole second in a handful of bits.
On a static screen recording you can comfortably run 1080p at 800 kbps and have it look sharp, which is well below what the table would suggest for that resolution. Text stays readable, which is usually the entire point. If your source is a screen capture, try the resolution one step above what the table recommends before you settle.
Setting it up
Choose Target size, set the ceiling to 20 MB if the recipient is unknown or 24 MB if you know they are on Gmail, and leave the format on MP4 — it is the one container you can send to a stranger and be confident opens.
For a screen recording, keep the original resolution. For camera footage over about three minutes, drop to 720p. If the clip is long enough that even 360p will not hold together, the honest move is a link: upload it somewhere and email the URL. The email compression page goes through the decision in more detail.
Questions about the 25 MB target
What is the Gmail attachment size limit?
Twenty-five megabytes for sending. Above that Gmail offers a Google Drive link instead of an attachment. Gmail will accept incoming messages up to about 50 MB, so the send limit is the binding one.
Why did my 24 MB attachment bounce?
Almost certainly base64 encoding. Attachments are encoded for transit, which adds about a third to their size, and many receiving mail servers apply their limit to that encoded size. A 24 MB file is roughly 32 MB on the wire. Target 18 to 20 MB if you do not know what the recipient runs.
Is 25 MB enough for a five-minute video?
For a screen recording or a talking head, comfortably — about 600 kbps, which holds up at 480p and often at 720p on static content. For handheld camera footage with movement, five minutes at 25 MB will look poor and you should either trim it or send a link.
Other size targets
- Compress to 5 MB The tightest ceiling here. Past about three minutes it stops being possible at all.
- Compress to 8 MB The classic chat and forum attachment wall. Tight enough that duration decides everything.
- Compress to 10 MB The default cap on a huge number of upload forms — and 25% more room than 8 MB.
- Compress to 16 MB The WhatsApp video ceiling — and the one target where the platform re-encodes after you.
- Compress to 20 MB The default in helpdesks, CMS media libraries and upload widgets. Rarely announced.
- Compress to 50 MB Roomy enough that 1080p survives on short clips. The first target that stops hurting.
- Compress to 100 MB Generous enough for real 1080p. Also GitHub's hard per-file push limit.
- Compress to 200 MB Big enough that the real question is your viewer's patience, not the platform's limit.
- Compress to 500 MB Discord Nitro's per-file ceiling, and the point where the browser becomes the bottleneck.
Compressing for a specific platform instead? Discord, WhatsApp and email each have their own page.
Or start from the file you have. Whether 25 MB is a stretch or a formality depends on what is already inside the container: MP4 , MOV , MKV , WebM , AVI , WMV , FLV , M4V and MTS / M2TS .