Compress a video for WhatsApp without going over 16 MB
WhatsApp caps videos at 16 MB and re-encodes everything anyway: here is the bitrate to aim for at each length, without ending up with pixel mush.
File too large. Three minutes of footage from a recent phone easily comes to 200 to 400 MB, and WhatsApp refuses point blank. The ceiling hasn’t moved in years: 16 MB per video sent inside a chat. So the whole job is getting your clip under that bar without making it unwatchable — and knowing when it is better to work around the limit than to bow to it.
What WhatsApp accepts, and what it does to your file
Three different limits live side by side in the app, and they get muddled all the time:
- Video sent via the paperclip icon → Gallery: 16 MB maximum. Above that, WhatsApp refuses to send it at all.
- The same file sent as a ‘Document’ attachment: up to 2 GB. No re-compression, but no preview either — the recipient has to download the whole file before they can play it.
- Status: 30 seconds per clip. Anything longer is split or truncated depending on the app version.
Rarely mentioned: even under 16 MB, WhatsApp re-encodes your video before sending it. The built-in encoder favours speed, so it drops the resolution and cuts into the bitrate without asking. The consequence is very concrete: the quality your contact sees depends on what you feed that encoder. A 300 MB 4K file squashed by force often comes out blurrier than a clean 720p file already down to 12 MB. Compressing it yourself beforehand isn’t punishing the file twice — it is what stops the worst from happening.
The only sum to do before you compress
The size of a video file is bitrate multiplied by duration. 16 MB is 128 megabits, but aim for 14 MB instead — 112 megabits — to keep some headroom: the container, the metadata and the encoder’s rounding eat up a few hundred kilobytes. Divide those 112 megabits by the length in seconds and you get the total bitrate — picture plus sound — that you can afford.
| Duration | Total bitrate available | Realistic resolution |
|---|---|---|
| 30 s | ≈ 3.7 Mbps | 1080p, no trouble at all |
| 1 min | ≈ 1.9 Mbps | 720p, comfortably |
| 2 min | ≈ 930 kbps | 720p if there is little movement, otherwise 540p |
| 3 min | ≈ 620 kbps | 480p |
| 5 min | ≈ 370 kbps | 360p, with visible artefacts |
These figures aren’t verdicts: the content matters as much as the arithmetic. A static shot of someone talking holds up very well at 600 kbps in 720p, because the background doesn’t move and the encoder has almost nothing to rewrite from one frame to the next. A football match, a handheld camera in the street or a fireworks display need three to four times as much to stay sharp. A screen recording of software, on the other hand, compresses remarkably well: large identical areas, very little noise.
The three levers, in order of effectiveness
1. Trim before you compress
This is the lever that pays off most, and the one most often overlooked. Since size = bitrate × duration, dropping the forty seconds you spent framing up the shot eases the constraint in exactly the same proportion. Going from 3 minutes to 45 seconds lifts the available bitrate from 620 kbps to nearly 2.5 Mbps: the same video moves from ‘mushy 480p’ to ‘flawless 720p’ without touching a single encoding setting.
2. Drop the resolution and the frame rate
Your contact will be watching on a 6-inch phone screen. 1280 × 720 is perfectly crisp there; 4K is pure waste in this context. Check the frame rate too: plenty of phones shoot at 60fps by default. Dropping back to 30fps cuts the bitrate you need by roughly a third. Doubling the frame rate does not double the cost — successive frames resemble one another more closely, so 60fps needs 50 to 60% more than 30fps rather than twice as much. The result looks identical on anything that isn’t sport or slow motion.
3. Don’t forget the audio track
It gets overlooked because you can’t see it, and yet it takes up space. Stereo AAC at 128 kbps costs 4.8 MB over five minutes — a third of the whole budget. For speech, 64 kbps in mono is more than enough and brings the bill down to 2.4 MB, all of it handed back to the picture. Save stereo at 128 kbps for clips where the music genuinely matters.
Doing it, in practice
Convertu’s Compress Video tool accepts MP4, MOV, AVI, MKV and WebM files. Processing happens on our servers — the video is uploaded, then deleted automatically after an hour. It comes down to four steps:
- Drop the file into the upload area (drag and drop, or click to browse) — check the maximum upload size shown beneath the area while you are there: over that, you’ll need to trim the clip on the phone first.
- Start the compression and let it work: on a video of a few dozen megabytes, expect tens of seconds rather than two.
- Download the slimmed-down MP4 and check how big it actually is before anything else.
- Play it all the way through, once. A file that squeezes under 16 MB but whose on-screen text you can no longer read is no use to anyone.
If the result is still above 16 MB, don’t run three compressions in a row on the same file: every pass re-encodes an already degraded source and the artefacts pile up. Go back to the original, cut the length, and start again from there.
The traps that stop a video getting through
A .MOV the recipient can’t play
iPhones record in HEVC (H.265) inside a MOV container by default — that’s the ‘High Efficiency’ setting under Settings → Camera → Formats. This codec is about twice as efficient as H.264, but not every older Android device decodes it, and some play it without sound. If you don’t know what the person at the other end is using, go back to an MP4 container with Convert Video Format: paired with H.264, it is the only genuinely universal combination today.
The video arrives rotated 90°
A video shot vertically isn’t always stored vertically: the sensor records in landscape and adds a rotation flag to the metadata. Some encodes lose that flag along the way, and the clip turns up on its side at the other end. The habit to build: play the compressed file on the sending phone, not just on the computer, before you fire it off.
Aiming for 15.9 MB
Bad idea. WhatsApp applies its own re-compression on top of yours and can, depending on the version, add a few kilobytes of metadata. A file calibrated right up against the ceiling sometimes gets refused with no explanation. Stay around 12 to 14 MB.
When only the sound matters
A recorded lecture, an interview, a filmed memo, a snatch of music: if nobody is really watching the picture, the video track is dead weight. Pulling the sound out with Extract Audio, or going through MP4 to MP3, changes the scale of the problem completely — ten minutes of speech in mono at 64 kbps comes to about 4.8 MB, and WhatsApp carries it without complaint.
Compress, or work around it?
Three situations, three different answers:
- A family memory meant to be watched on a phone: compress to 720p and send it as a video. Playback straight from the chat, and the preview alongside it, are well worth the loss of definition.
- A file someone has to edit, archive or retouch: leave it alone. Send it as a ‘Document’ attachment (up to 2 GB) or share a link instead. Compressing rushes before handing them to an editor means giving them a damaged source.
- A video for a Status: cut it to 30 seconds before compressing. That way you claim the whole available bitrate for the part you actually keep.
Video compression runs on our servers: like most of the heavy jobs in the catalogue (PDF, video, HEIC, background removal), it can’t be done in the browser. The text and calculation tools, by contrast, never leave your machine. One conversion a day is free with no sign-up; beyond that, unlimited access to every tool costs €7 a year, cancellable in one click.