Speed up audio
Listen in less time, with voices that still sound like themselves.
- Nothing is uploaded
- Works offline after first use
- Open source
- No watermark · limit is your device’s memory; phones hold less
Speed up an MP3, podcast, lecture or voice memo in your browser and keep the voice at its normal pitch. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after your first run to save itself for offline use, and then it works offline.
Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
Players can speed up playback, but a saved faster copy is handy for a phone that cannot, a clip that has to fit a time limit, or a voice memo you will send on. This page makes that copy at 1.25× to start with; pick anything from 1.05× to 2×.
A worked example: a 48-minute lecture recording at 1.25× comes out at 38 minutes 24 seconds, and at 1.5× at 32 minutes. Divide the length by the speed to see where you will land. A 75-second voice note that has to fit a 60-second limit needs 1.25×, and it still sounds like the person who recorded it.
The pitch stays where it was, so speech stays clear rather than squeaky. That matters most for voices: a lecturer at 1.5× sounds like a fast talker, not a cartoon. If you want the bright sped-up-song sound used in short video edits, tick the option that lets the pitch follow the speed, and 1.25× then also raises the key by almost four semitones.
The copy is written in the format you dropped unless you pick another, at about the original bitrate, so a 64 kbps podcast does not balloon into a big file. Meetings, interviews and lectures often contain things that should not leave your laptop; this page never sends them anywhere.
How it works
- Drop one or more MP3, WAV, M4A or other sound files.
- Pick the speed. Leave the pitch at 0 to keep voices natural.
- Run it. Each faster file downloads when it is ready.
In your browser, not on a server
Your browser’s own audio decoders read the file in the tab. The speed is changed with WSOLA (waveform-similarity overlap-add): the sound is cut into overlapping 43 ms windows, spread out or packed together, and each window is nudged to line up with the one before so there are no clicks. The pitch is then moved by resampling through a windowed-sinc filter, which also shortens or lengthens the sound, so the stretch is sized to leave exactly the speed you asked for. The result is written with the same encoders as the audio converter.
Compared with upload-based tools: Online pitch shifters upload the whole song or recording and many cap the length or the number of files on a free plan. Here the file never leaves your device, a whole album can go in one batch, and nothing is added to the sound.
Verify it yourself. Give the page a short while after your first run to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
What speed is best for podcasts and lectures?
Most people follow speech easily at 1.25× to 1.5×. Above 1.75× only very clear speakers stay comfortable, and background music starts to sound choppy before the voice does.
Can I make a sped-up song for TikTok or Reels?
Yes. Tick “Let the pitch follow the speed” for the higher, brighter sped-up sound those edits use, or leave it off to keep the key. 1.2× to 1.3× is the usual range for sped-up versions of songs.
Why is my file shorter but the same size in MB?
A lossy file is written again at about the bitrate of the original, and size follows bitrate times length. A file that plays 25% faster is 20% shorter, so it should be about 20% smaller. If the size did not drop, the original was probably a low-bitrate file saved at a higher rate; pick MP3 and it is written at a sensible bitrate.
Does speeding up remove pauses?
No. Everything plays faster by the same amount, pauses included. To cut silences out of a recording, trim them with Trim audio first, then speed up what is left.
Is the file uploaded anywhere?
No. There is no server in this process. The page is a static file and the work is done by code running inside your browser tab. Give the page a short while after your first run to save itself for offline use; then you can turn off Wi-Fi and it still works.
More video and audio tools
Pitch and speed changer
Change the key of a song, or play it faster or slower, keeping the other the same. Done on this device.
Voice recorder
A voice memo, a voice-over or a quick demo, recorded in this tab and saved as MP3. The sound never leaves your device.
Volume booster
Boost a quiet recording, turn down a loud one, or even out a batch. Done on this device, never uploaded.
Remove background noise
Keep the voice, lose the hiss, hum and fan noise. Cleaned on this device, never uploaded.