Speed a video up or slow it down
A lecture at 1.5× with the lecturer still sounding human, or a tutorial slowed to 0.75× so the steps can be followed — the pitch checkbox is the difference between useful and chipmunks.
- Runs entirely in your browser
- Works offline
- No upload
- No sign-up
- No watermark
Loading the tool…
How it works
- Drop a video or audio file.
- Set the speed and decide whether the pitch should stay natural.
- Start, and download the result.
Why nothing is uploaded
Every operation on this page is done by code running inside your browser tab, using the same engine that renders web pages. The file is read from disk into your tab’s memory, transformed there, and written back out as a download. It is never sent anywhere — not to us, not to a third party.
Verify it yourself
- Open your browser’s developer tools (F12) and select the Network tab.
- Load your file and run the tool.
- The only requests you will see fetch the tool’s own code — and, for a few heavy tools, their open-source engine from a public CDN — plus one small page-view ping to loreatec.jp (page address and title, nothing more). None of them carry your file.
Frequently asked questions
What does the pitch option actually change?
Speeding audio up naturally raises its pitch — the tape-fast-forward effect. With correction on, the tempo changes but voices keep their register, which is what you want for speech. Off is for when the shifted pitch is the point.
Why only 0.5× to 2×?
Because that is the range where a single pitch-corrected pass sounds clean. Beyond it, artefacts stack up quickly and a wider slider would only look better on paper. Run the output through again for 4× if you accept the quality cost.
Does the video re-encode?
Yes — changing every frame’s timestamp requires it. Expect the usual encoding time and a generation of quality; the audio is processed in the same pass.
Is my video uploaded?
No. The video engine is compiled to WebAssembly and runs inside this tab; the file is read from disk into memory and the result is written back out. Nothing is transmitted, which is why a two-hour film will not work here — your device is doing all of it.