Compress video online — without uploading it anywhere

Shrink a video to an exact file size or a quality level, directly in your browser. Your file is processed on your own device using your browser's built-in video hardware — it is never uploaded, so there's no waiting for a 500 MB upload to crawl to a server and back.

How it works

Drop in a video (MP4, MOV, WebM, MKV or AVI) and choose one of two modes. Target size calculates the exact bitrate needed to land your video under a size limit — 8, 10, 16, 25 or 50 MB, or any number you type in. It budgets the audio first, gives the rest to video, and automatically lowers resolution or frame rate when a long video has to fit a small target, so you get the best quality the budget allows. Quality mode simply re-encodes at high, medium or low quality when you don't care about an exact number.

Everything happens on your device. Modern browsers ship a hardware-accelerated video engine (WebCodecs), which VidKit uses to compress faster than the video plays. For older browsers or unusual formats, a built-in software encoder takes over automatically — slower, but it works. A status line under the progress bar shows you which engine is running.

The result is a standard MP4 (H.264 video, AAC audio) that plays everywhere: Discord, WhatsApp, email clients, iPhones, Androids, smart TVs. You preview the compressed video side by side with the original before downloading, so you never download a result you haven't seen.

Frequently asked questions

Is my video really not uploaded?
Really. The compression runs in your browser using your computer's own processor — there is no upload, and the site has no server that could even receive your file. You can verify this yourself: open your browser's developer tools, watch the Network tab while compressing, and you'll see zero requests carrying file data.
Is there a file size limit?
On a modern browser (Chrome, Edge) files up to 2 GB are supported. Very large files in older browsers may be refused with a clear message rather than crashing — if that happens, try Chrome.
Will there be a watermark?
No. The output is your video, just smaller — no watermark, no outro, no branding, free.
How much quality will I lose?
That depends on how hard the video is squeezed. Halving a file's size is usually invisible. Fitting a 10-minute video into 10 MB means visible quality loss — the tool lowers resolution and frame rate gracefully instead of producing a blocky mess, and tells you the output dimensions before you download.
What formats can I compress?
Input: MP4, MOV, WebM, MKV and AVI, with H.264, H.265/HEVC, VP8, VP9 and most common codecs. Output is always MP4 with H.264 video and AAC audio — the most compatible combination there is.
Does it work on a phone?
Yes — Chrome on Android and Safari on iOS both work. Phones have less memory than laptops, so very large files are more likely to need a desktop browser.