Compress a video on your iPhone, no app

This page is the compressor, and it runs on the phone you are reading it on. Tap the box, pick the clip out of your Photo Library, and the encode happens inside the browser tab — nothing installed, nothing uploaded, no account. Below the tool is what a phone can realistically manage and how to stay inside it.

Drop your video here

or click to browse — MP4, MKV, MOV, WebM, AVI and more

The whole procedure

  1. Tap the drop zone above. iOS offers Photo Library, Take Video and Browse — the first one is what you want for something already recorded.
  2. Pick a mode. Target size if something has given you a number to come in under; the quality slider if you just want the file meaningfully smaller.
  3. Set the resolution to 720p unless you have a reason not to. On phone footage it is the single biggest saving available, and on a phone screen it is close to invisible.
  4. Run it, leave the tab in the foreground, and download the result. On iOS it lands in Files under Downloads, ready to save back to Photos or attach to a message.

Keep the screen awake while it works. A backgrounded or locked tab gets its CPU throttled hard by the phone, and an encode that would take two minutes in the foreground can crawl or stall entirely behind the lock screen.

Memory is the real ceiling, not the file size limit

There is no size cap here, because there is no server imposing one — but a phone gives a browser tab far less memory than a laptop does, and the whole file lives in that tab while it is encoded. That is the limit you will meet, and it arrives as a failed encode rather than a polite refusal. The tool recognises the case and tells you the run ran out of memory instead of hanging on a progress bar.

Three things buy you room, in order of how much they buy: trim the clip to the part you actually need, drop the resolution a step, and close the other tabs. A long 4K recording is the case that will not fit on a phone at all — that one belongs on a laptop, or trimmed hard first.

A worked example: three minutes under 25 MB

A three-minute clip that has to fit a 25 MB mail attachment leaves the video stream about 990 kbps once 128 kbps of audio and the container overhead are taken out. That is a 720p budget — the figure the tool solves for this clip, and the reason the resolution step matters more on phone footage than anywhere else. The source is usually 1080p or 4K at a bitrate no attachment limit can hold, so handing 990 kbps to a 1080p frame spreads it across more than twice as many pixels as 720p would have asked it to cover, for no visible gain on a phone screen.

Why not just let the app do it

Messaging apps re-compress video on the way out, and they do it to their own budget rather than yours: the clip is squeezed to whatever the app considers acceptable, usually with no control over the result. Compressing first means the file arrives inside the limit already, so the app has far less left to take away. It also fixes the other phone problem — an iPhone recording HEVC that the recipient's device cannot decode. Output MP4 with the codec on H.264 and it plays everywhere.

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