Compress MP4 videos.
Shrink MP4s on your device — under any upload size limit.
Drop MP4 files here
or browse your files
Paste with ⌘V · or drop files anywhere on the page
Files never leave your device. Everything runs in your browser, nothing touches a server — tools you've used even work offline.
Compress MP4 files right on your own device — no upload, no queue, no watermark. Set a quality for a smaller look-alike, or type the limit you’re fighting and target-size mode finds the settings that fit. Audio is carried over untouched whenever possible.
Before / after
Original
40.2 MB
Compressed
10.3 MB
Saved
−74%
The clip above is a real second run through the same tool — quality 50 plus a 640 px resize: 40.2 MB → 770.8 KB, playing exactly as the tool wrote it.
Real result, not a mock-up: this 3840 × 2024 (4K), 13.3-second MP4 clip went through the Compress MP4 tool — H.264 via WebCodecs, the encoder built into your browser, at quality 75 with a 1920 px cap, the guide's own website preset — and dropped from 40.2 MB to 10.3 MB. The slider compares the same frame of both files, 6.3 seconds in: the original at native 4K, the compressed clip scaled back up for like-for-like framing, so the slight softness you can find is the real cost of the 1080p trade. Quality 75 maps to a bitrate matched to the new resolution; the byte counts refer to the complete clips. Press play below to watch the result in motion — or drop the same video in yourself and you'll get the same number.
Video via Magnific .
How it works
- Drop files anywhere on the page, click to browse, or paste with ⌘V.
- Pick a quality or preset — or set an exact target size and let the tool find it.
- Compress, compare before/after, and download — individually or as a ZIP.
Quality mode vs target-size mode
Quality mode is for “make it smaller, keep it looking good” — the tool picks settings matched to resolution and frame rate. Target-size mode is for hard limits: it works backwards from your number and the clip duration, so a 90-second clip and a 9-minute clip both land under the same cap — the long one just looks softer.
Recommended targets by destination
| Destination | Setting |
|---|---|
| Discord (free tier) | Target size: 10 MB |
| Email attachment | Target size: 19 MB |
| Website or CMS upload | Quality 70, max dimension 1920 px |
| Compatible master copy | Quality 90, original size |
Why MP4 is the safe output
MP4 (H.264) plays on effectively everything made this decade — Windows, Android, TVs, editors, browsers, upload forms. If your source is a newer iPhone recording (HEVC), converting costs some efficiency but buys universal playback; keep the quality higher to compensate. For the smallest file where compatibility doesn’t matter, the Compress video tab’s WebM output beats it.
Under the hood
Compression runs on WebCodecs — the H.264 encoder built into your browser, usually the same hardware block that records your screen — while mediabunny does the container work of reading the source MP4 and writing the new one around the fresh video track. The quality slider maps to a bitrate matched to the clip’s resolution and frame rate, capped so the re-encode never spends more bits than the original. Everything happens on your device, which is why there is no upload, no queue and no watermark.
Frequently asked questions
How much smaller will my MP4 get?
Phone and screen recordings typically shrink 50–80% at the default quality, because they were encoded generously at capture time. Videos that were already compressed hard shrink less — the tool keeps the original if it can’t beat it.
How do I fit Discord or email limits?
Switch to target-size mode and type the cap itself — 10 MB for Discord’s free tier, 19 MB to send reliably by email. The tool aims the file at your number and lands just under it.
Will it lose quality?
MP4 is lossy, so re-encoding trades some detail for size — at the default quality the difference is hard to spot on phone footage. HDR sources are tone-mapped to standard colors; the tool warns you when that applies.
Is my video uploaded?
No. Encoding runs on your own hardware from first frame to last — nothing streams to a server, which is also why there is no file-size cap and no queue. Close the tab and every trace of the footage is gone. Want proof? Run one file through, switch your connection off, and run another — it still works.