Compress Video to a Target Size

Compress video that is too big for email, chat or an upload form. Pick the size you need – the tool works out the right bitrate and resolution and re-encodes the video in your browser. Your video is never uploaded.

Source: MDN – VideoEncoder.configure(): bitrate in Bit pro Sekunde. Updated: 28 September 2026.

How it is calculated

Make a video fit a size limit

Many services cap file size: email attachments (Gmail allows 25 MB according to Google's help page), chat apps, upload forms for schools, jobs or shops. Instead of guessing with a quality slider, you enter the target size directly and the tool calculates the matching bitrate.

How it works

Drop or choose a video (MP4, MOV from an iPhone, WebM, MKV).
Choose a target size such as 10 MB, or enter your own. The planned resolution and bitrate appear below.
Click “Compress video”. You can play the result right away and download it.

The maths behind it

Video size is bitrate × duration. For 10 MB and 60 seconds that leaves 10,000,000 bytes × 8 ÷ 60 s ≈ 1,333 kbps. The tool keeps 4% free for the file structure, subtracts the audio (here 96 kbps) and uses the rest for the picture: about 1,184 kbps. To avoid a blocky image, it lowers the resolution until each pixel gets enough data – in this example 960 × 540 instead of Full HD. 1 MB counts as 1,000,000 bytes; that is the smaller reading of “MB” and therefore the safe one.

Target	Length	Total bitrate	Typical resolution
10 MB	30 s	approx. 2,560 kbps	1280 × 720
10 MB	60 s	approx. 1,280 kbps	960 × 540
25 MB	3 min	approx. 1,067 kbps	960 × 540
50 MB	10 min	approx. 640 kbps	640 × 360

Encoding uses H.264 with AAC audio in MP4 – the format virtually every phone and player can play. Encoders never hit the bitrate exactly. If the result is larger than the target, the tool automatically runs another pass with a lower bitrate (three at most).

Honest limits

Browser: encoding uses the WebCodecs API, available in current Chrome, Edge, Safari and Firefox but not in every older browser.
Speed: depending on the device it takes about as long as the video, or less. Long 4K videos need patience, and the tab must stay open.
Quality: there is no magic. A ten-minute video at 10 MB will be small and soft. Trimming it first helps – Trim video does that without quality loss.
Platform limits change; if in doubt, check your service's current limit and choose a little below it.

Privacy

The video is read piece by piece from your device and re-encoded in the browser. There is no upload and no server processing. Reading and writing the video files is handled by the open-source library Mediabunny (MPL-2.0), which only loads when you pick your first video.

More media tools: Video to MP3 and Video to GIF.

Frequently asked questions

Is my video uploaded?

No. The video is read and re-encoded in your browser. It never leaves your device.

How do I compress a video to 10 MB?

Drop the video, choose 10 MB as the target size and click “Compress video”. The tool sets bitrate and resolution so the file ends up at most 10 MB, and checks the result.

How do I compress a video to send by email?

Choose a target a little below your email provider’s attachment limit – Gmail’s help page names 25 MB – and compress. Longer videos get a lower resolution so they fit.

Can I compress a video without losing quality?

Not noticeably smaller. Only cutting parts away is lossless. Making a file much smaller means re-encoding, which drops detail – barely visible with generous targets.

Why does the resolution go down?

With little data, a smaller clean picture looks better than a large blocky one. The tool lowers the resolution step by step (1080p, 720p, 540p …) until each pixel gets enough data.

Does it work on iPhone?

Yes, in current Safari. iPhone videos (MOV, H.264 or HEVC) are read and saved as MP4 with H.264, which almost every device can play.

Sources and legal basis

As of: 28 September 2026