Is Change video speed free? Is there a watermark?

Yes — Change video speed is free to use with no sign-up or watermark. Very large files can still be limited by your browser's available memory and processing resources.

Do my files get uploaded to a server?

No. Change video speed runs entirely in your browser with WebAssembly, so your MP4, MOV, WebM (with audio) file never leaves your device and nothing is stored or seen by us.

What can I put in, and what do I get out?

Change video speed accepts MP4, MOV, WebM (with audio) and gives you back a MP4 file. You can also set speed before you run it. Actual codec support depends on what the bundled engine or browser decoder can read.

Does Change video speed change my original file?

No. It never touches your original — Change video speed creates a brand-new MP4 file to download and leaves the source on your device untouched.

Free tools · Edit

Change video speed

Make a video faster or slower — 0.5× to 2× — with the audio kept in sync. Great for time-lapses or slow-motion. Browser-only, no upload.

Runs entirely in your browser. Your file is never uploaded — no watermark, no account.

Drop a file or click to chooseMP4, MOV, WebM (with audio)

Get a better result

Best for: Shortening tutorials, accelerating process footage, or creating simple 0.5×–2× timing changes when the source includes an audio stream.
Input → output: Video timing is adjusted with setpts while audio uses atempo, then both become H.264 MP4 and AAC with synchronized duration.
Quality tip: Use the smallest speed change that communicates the idea. Review speech intelligibility and motion cadence, especially at 0.5× and 2×.
Know before running: A silent source can fail because the filter expects audio. Slowing does not interpolate new motion frames, and speeding cannot remove motion blur already captured.
Next step: Change frame rate when the retimed clip needs a specific delivery cadence.

How to use Change video speed

1
Choose your file. Drop a supported MP4, MOV, WebM (with audio) file into the tool, or click to select one. It stays on your device — nothing is uploaded.
2
Pick your settings. Adjust the available options, then press Run. The first processing run loads the browser engine before conversion begins.
3
Download. Review the result, then download the finished file from your browser with no watermark.

Frequently asked questions

Is Change video speed free? Is there a watermark?: Yes — Change video speed is free to use with no sign-up or watermark. Very large files can still be limited by your browser's available memory and processing resources.
Do my files get uploaded to a server?: No. Change video speed runs entirely in your browser with WebAssembly, so your MP4, MOV, WebM (with audio) file never leaves your device and nothing is stored or seen by us.
What can I put in, and what do I get out?: Change video speed accepts MP4, MOV, WebM (with audio) and gives you back a MP4 file. You can also set speed before you run it. Actual codec support depends on what the bundled engine or browser decoder can read.
Does Change video speed change my original file?: No. It never touches your original — Change video speed creates a brand-new MP4 file to download and leaves the source on your device untouched.