Free tool

Compress Video to Any File Size

Tell the tool how big the file may be and it works out the rest: it divides your size by the video's length, chooses a resolution that bitrate can carry, and shows you the plan before it starts. To compress video this way nothing is uploaded: the whole job runs in your browser tab.

01 — Your video

Choose a video

02 — Result

Your new file

Choose a video and press Compress video. It runs in this tab, so the video never leaves your computer or phone.

How to compress video to a target size

  1. Choose the video above: MP4, MOV, M4V, WebM or MKV. The tool reads its length, picture size and frame rate from the file.
  2. Pick a target from the chips (8, 10, 25, 50 or 100 MB), or type any whole number into "Or a size in MB".
  3. Read the plan under the settings: the picture size it will use, the video bitrate in kbps, the sound bitrate and the expected file size. Any note about lowering the resolution or frame rate appears here too.
  4. Press "Compress video" and keep the tab open. How long it takes depends on your device and on the clip.
  5. Check the result card, which shows the new size next to the original, then download the MP4. If the file came out over your target, press "Try again 20% smaller".

How target-size compression works

A video's size is its bitrate multiplied by its length. Turn that around and a size limit becomes a bitrate budget: divide the target by the duration and you know how many bits each second may use. The compressor does that arithmetic first and then decides how to spend the budget.

Target size
25 MB, counted as 25,000,000 bytes, the way upload limits are usually quoted
In bits
200,000,000, at 8 bits per byte
Clip length
2 minutes, which is 120 seconds
Budget
about 1,667 kbps for picture and sound together
Headroom
a few percent held back for the file's container and for encoder overshoot

Sound takes its slice first. The tool re-encodes it to AAC at a modest bitrate, roughly a tenth of the budget and never more than 128 kbps, and drops it to 32 kbps when the budget is very tight. Speech stays understandable at those rates; music loses some sparkle at the low end. Everything left goes to the picture. For the background on rate control and file-size sums, see video bitrate explained.

Why the resolution drops

Every frame shares the same budget. A 1080p frame has 2.25 times as many pixels as a 720p frame, so the same bitrate spread over it leaves less data per pixel, and H.264 starved of data shows blocks, smeared faces and banding in skies. Instead of handing you a blocky 1080p file, the planner walks down a ladder of heights (2160p, 1440p, 1080p, 720p, 540p, 480p, 360p, 240p) until each frame gets enough data to look clean. It never scales a video up.

In the 2-minute example above, a 1080p recording at 30 fps would come out at 720p: after the sound and the headroom, roughly 1.36 Mbps remains for the picture, which is thin for 1080p detail but comfortable at 720p. A 60 fps clip on a tight budget is also lowered to 30 fps, which halves the number of frames sharing the data. The plan readout tells you when either change happens and why.

If you would rather choose the size of the picture yourself and let the file size follow, the change video resolution tool scales to a height you pick and keeps the shape.

Why nothing can simply be copied

Some tools on this site finish in seconds because they copy the compressed picture into a new file untouched. Compression can't work that way: the only way to make the picture take fewer bits is to decode every frame and encode it again at a lower bitrate. So this is always a full re-encode, done with the browser's WebCodecs API, and the output is an MP4 using H.264 when your browser can encode it, or another codec the browser supports when it can't.

That makes speed a property of your device. A short phone clip finishes quickly; a long 4K recording on an older laptop can take longer than the video runs. A smaller output resolution helps a little, because the encoder has fewer pixels to process. Re-encoding needs a browser with WebCodecs video encoding: current Chrome or Edge, Safari 16.4 or later, or Firefox 130 or later on a computer. Large results are written to the browser's private storage when it offers it, rather than held in memory.

What quality to expect

How good a compressed video looks depends more on what is in it than on how long it is.

  • Talking heads, slides and screen recordings have little motion and compress well; at a generous target the difference from the original is hard to spot.
  • Sports, handheld walking shots, confetti, rain, water and film grain change nearly every pixel in every frame and need far more data. Expect visible softness at the same size.
  • Small text in a screen recording blurs once the resolution falls below the size it was captured at. If the text matters, send a shorter clip rather than squeezing a long one hard.
A 40-second product demo for a 10 MB limit

10 MB over 40 seconds is about 2 Mbps in total. A 1080p screen recording of a calm desktop holds up well at the 720p the planner picks; a 1080p skateboarding clip at the same size looks noticeably softer, because motion eats the budget.

A 12-minute lecture squeezed into 25 MB

The budget works out at under 280 kbps for everything. The planner gives the sound 32 kbps and drops the picture all the way to 240p. It plays, but the slides become unreadable, so splitting the lecture or sharing a link serves viewers better.

When the target is too small or overshoots

If the target leaves too little for the picture to be watchable even at the bottom of the ladder, the plan says so and the compress button stays disabled. Two ways out: shorten the video with the trim tool, whose fast mode copies the part you keep without re-encoding, then compress the shorter clip; or choose a larger target.

The encoder works to an average bitrate, and busy scenes can push the real size above it, so the planner already aims a little under your number. If the result still lands over the target, the result card says by how much and offers "Try again 20% smaller", which reruns the job with a budget one fifth lower.

Presets for common limits

Each sharing service has its own ceiling, and their help pages don't always agree with each other. These pages carry their own size presets and explain where the figures come from:

If only the sound matters, for example a recorded talk someone will just listen to, the audio compressor makes a far smaller file than any video can.

Subtitles or a translation afterwards

Compressing happens entirely in your browser tab and the video is never uploaded. If you later want subtitles or a dubbed version, there's no need to compress first: the video translator opens the original file in the browser and uploads only its audio track for the AI work, so even a large recording doesn't cost extra upload time.

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Frequently asked questions

Why did my compressed video come out at a lower resolution?

The target size gives each second a fixed amount of data, and at full resolution that data is spread too thin, which shows as blocks and smearing. The planner steps down to the highest resolution that still gets enough data per pixel, and the plan readout tells you before you start.

Can a video be made smaller without losing any quality?

Not by re-encoding: lowering the bitrate always discards some detail, although at a generous target the difference is hard to see. The only lossless ways to shrink a file are to remove parts of it, such as cutting its length or dropping the sound.

How long does it take to compress a video in the browser?

It depends on your device and on the clip's length and resolution, because every frame is decoded and encoded again. Short phone clips finish quickly, while long 4K footage on an older computer can take longer than its running time. Keep the tab open until the download appears.

Why is the compressed file bigger than the size I picked?

The encoder works to an average bitrate, and scenes with a lot of motion can need more than the average. The tool aims slightly under your target, and if the result still overshoots it offers to run again with a 20% smaller budget.

Is my video uploaded when I compress it?

No. The file is read and re-encoded inside your browser tab and the MP4 is saved from there; nothing is sent to a server.

What happens to the sound when a video is compressed?

It is kept and re-encoded to AAC at a bitrate taken from the size budget, at most 128 kbps. On very small targets it drops to 32 kbps, which keeps speech understandable but flattens music.