Reduce a video's file size
There are exactly four levers that make a video smaller: bitrate, resolution, frame rate and audio. Everything calling itself an "AI compressor" is pulling those same four. Here they are, unhidden.
Reduce a video's file size
Pick a quality level; the file comes out as big as this clip needs.
Choose a video or drop it here
Read by this page, never uploaded. MP4, MOV, MKV, WebM, AVI, WMV, FLV and more.
Resolution, frame rate, audio, codec
Nothing is uploaded
FFmpeg runs in this tab. Turn your Wi-Fi off after the page loads and it still works.
Hit an exact size
Say "under 25 MB" and the bitrate is solved for you, two-pass.
No account, no watermark
No sign-up, no email, no logo burned into your video.
No file-size cap
No 100 MB paywall. The only limit is your browser's memory, around 2 GB.
There are exactly four levers
Every video compressor on the internet, whatever it calls itself, is pulling some combination of these four. Nothing else is available to any of them.
| Lever | Typical saving | What you give up |
|---|---|---|
| Bitrate (quality) | 30–80% | Detail in motion first, then everywhere |
| Resolution | 1080p→720p: ~55% 1080p→480p: ~80% | Sharpness on big screens; often invisible on a phone |
| Frame rate | 60→30 fps: ~40% | Smoothness of motion |
| Audio | A few MB | Fidelity, or the sound entirely |
The reason "AI compression" marketing is mostly noise: there is no fifth lever. A better encoder spends the same bits more cleverly, which is real but incremental — the order-of-magnitude savings come from resolution and bitrate, and they always have.
Which lever to pull, in order
- Is it bigger than it needs to be displayed? A 4K clip destined for a phone screen is carrying four times the pixels anyone will see. Downscale first — it is the cheapest quality-per-byte decision available.
- Was it shot at 60 fps for no reason? Action footage benefits. A person talking does not.
- Now lower the quality. With the frame right-sized, CRF 24 is usually indistinguishable from the original at normal viewing distance.
- Audio last. 128 kbps AAC is transparent for almost everything; 64 kbps is fine for speech. Removing it entirely only makes sense when you know nobody needs it.
What compression cannot do
It cannot recover detail that was never recorded, and it cannot make an already-compressed file smaller for free. Each re-encode is generational loss: compress a file that has been compressed twice already and it will look worse than the numbers suggest. When you have the original, always start from it.
It also cannot beat arithmetic. An hour-long clip cannot become a good 10 MB file, and any tool that implies otherwise is about to hand you something unwatchable.
How it works
Pick your video
It is read straight from your disk by this page. No upload, no queue, no account.
Choose a quality level
Balanced is visually indistinguishable on a phone or laptop at normal viewing distance.
Compress in the tab
FFmpeg runs in WebAssembly on your own machine. The first run downloads a 31 MB engine, once per browser.
Download it
The result is handed back as a file. Nothing was sent anywhere, so there is nothing to delete afterwards.
Compress for a specific limit
Compress a video for email
Targets 20 MB by default.
Open the compressor →Compress a video for Discord
Targets 9 MB by default.
Open the compressor →Compress a video for WhatsApp
Targets 15 MB by default.
Open the compressor →Compress a video to 8 MB
Targets 7.5 MB by default.
Open the compressor →Compress a video to 25 MB
Targets 24 MB by default.
Open the compressor →Compress an MP4
Quality-based, no target to pick.
Open the compressor →Compress a MOV file
Quality-based, no target to pick.
Open the compressor →Compress a video for Instagram
Quality-based, no target to pick.
Open the compressor →Compress a 4K video
Quality-based, no target to pick.
Open the compressor →Questions people actually ask
Short answers here, the full story in the guides.
Is my video uploaded to a server?
No. The compressor is FFmpeg compiled to WebAssembly and it runs inside this browser tab. Your file is read from disk by the page, processed in memory, and handed back to you as a download. You can load the page, disconnect from the internet, and compress anyway — which is the simplest proof there is.
Does compressing a video lose quality?
Yes, always — compression works by throwing information away. The honest question is whether you can see it. At a sensible bitrate for the resolution, most people cannot tell on a phone or laptop screen. Anyone promising "no quality loss" is describing the perception, not the file.
How do I compress a video to an exact size?
Switch the tool to Target size and type the number. It reads the clip's duration, subtracts the audio budget, solves for the video bitrate that fits, and encodes two-pass so the result lands under the target rather than near it.
Is there a file size limit?
No limit we impose, but a browser tab is bounded by WebAssembly's ~2 GB of memory, and a re-encode needs roughly three times the file's size free. Files up to a few hundred MB are comfortable. Above about 1 GB, the iPhone app is the better tool.
Is there a watermark?
No. No watermark, no logo, no intro frame, no account, and no upload cap to unlock by paying. The output is your video, compressed.
Which format should I compress to?
MP4 with H.264 video and AAC audio, unless you have a specific reason not to. It plays on effectively everything. H.265 gives you a smaller file at the same quality but encodes much slower here and is refused by some uploaders and older devices.
Compressing on a phone?
The iPhone app does this on the device, with the hardware encoder.