About the Audio Speed Changer
Audio Speed Changer speeds up or slows down a sound file, changes its volume, and can play it backwards. Pick a file, choose a speed from 0.25 times to 4 times, set the volume from minus 20 to plus 20 decibels or normalise it to full volume, and tick Reverse if you want it backwards. The page shows the new length, plays the first 20 seconds as a preview and saves the result as a WAV file. Changing the speed also changes the pitch, like a tape or record played faster or slower, because there is no time-stretching that keeps the pitch. If the volume pushes the sound past full scale it is clipped and can sound harsh, so the page counts the clipped samples. Nothing is uploaded, and your original file is not changed.
Updated September 2026
How to use the Audio Speed Changer
- 1Select an audio file such as MP3, M4A, OGG, FLAC or WAV.
- 2Choose a speed preset or type your own from 0.25 to 4.
- 3Set the volume, or tick Normalise. Tick Reverse to play it backwards.
- 4Press Play preview to listen, then Save as WAV.
Speeding up and slowing down audio
Choose a preset from 0.5 times to 2 times, or type any speed between 0.25 and 4. A speed of 2 makes the audio half as long, and 0.5 makes it twice as long. The line below the controls shows the new length, for example 3:20 to 1:40. Speeding up is handy for lectures and long recordings, and slowing down helps when you want to pick out words or learn a passage of music.
Why pitch changes with speed
The tool changes speed by reading the sound at a different rate. It is like playing a record faster or slower: everything gets shorter and higher, or longer and lower, together. Small changes such as 1.25 times sound natural. Large changes make voices sound like chipmunks or slow giants. Keeping the pitch while changing the speed needs more complex processing, which this page does not do.
Making audio louder without distortion
- Volume is set in decibels. Plus 6 dB roughly doubles the signal, and minus 6 dB halves it.
- Normalise raises the loudest point to full volume, which is the safest way to make a quiet file louder.
- If a boost pushes a sample past full scale it is cut off, which is called clipping and sounds harsh.
- The page counts the clipped samples after you preview or save, so you can lower the volume and try again.
- Normalising ignores the volume slider.
Reversing and other quick edits
Reverse plays the sound backwards, which is fun for effects and for checking what a recording sounds like from the end. Speed, reverse and volume can all be combined, and they are applied in that order: speed first, then reverse, then volume.
For a longer file, cut out just the part you need first with Audio Trimmer. To record something new use Voice Recorder, to turn text into speech try Text to Speech, and to capture the screen with sound see Screen Recorder. Need to convert between units? Unit Converter can help. The result is saved as an uncompressed WAV.
Features
- Speed from 0.25 times to 4 times
- Volume from minus 20 to plus 20 decibels
- Normalise to full volume in one tick
- Reverse audio
- New length shown, with a clipping warning
- Preview of the first 20 seconds
Frequently asked questions
How do I speed up an audio file?
Select the file and choose a speed above 1, for example 1.5 or 2. The new length is shown next to the controls. Press Play preview to listen to the first 20 seconds, and Save as WAV to keep the whole result.
Does changing the speed change the pitch?
Yes. Here the pitch rises when you speed up and drops when you slow down, like a record played at the wrong speed. The page doesn't have time-stretching that keeps the pitch the same, so voices can sound higher or deeper at extreme speeds.
How do I make audio louder?
Raise the Volume slider, which goes up to plus 20 decibels, or tick Normalise to full volume. Normalise finds the loudest point and scales everything so that it just reaches full scale. If the sound goes past full scale it is clipped, and the page tells you how many samples were affected.
How do I reverse audio?
Tick Reverse. The result plays from the end to the start. If you also change the speed, the speed change is applied first and then the sound is reversed.
What does normalise mean?
It raises or lowers the whole file by the same amount so that the loudest sample reaches full volume, without changing how loud the parts are compared with each other. When it is on, the volume slider is ignored.
Is my audio uploaded?
No. The file is decoded and processed by your browser on your device. Nothing is sent to a server, and your original file is never changed.
What format is the result?
An uncompressed WAV file, which is much bigger than an MP3. The page has no MP3 encoder. Results longer than 30 minutes are refused, so choose a higher speed or trim the audio first.