UtilibyWritten by the Utiliby editorial team · Last updated October 13, 2026 · Rules and formulas reviewed October 2026
What this free audio speed and pitch changer does
People change the speed of audio for many reasons: to slow a difficult guitar solo for practice, to listen to a podcast in less time, to match the tempo of two tracks, to make a nightcore edit, or to lower a song into a singer's range. Doing it well used to need a digital audio workstation or a paid app, because simply playing audio faster also raises the pitch. This free online tool lets you change speed and pitch separately, right in your browser, with a quick preview before you download.
It offers two modes. Keep pitch mode uses a time stretching method to change speed without changing pitch, and a pitch shift in semitones without changing speed. Linked (tape) mode changes both together, like a record player. Both modes work on MP3, WAV, M4A, OGG and FLAC. Your file stays on your device, and there is no sign-up and no watermark.
How to change speed or pitch in four steps
- Load your audio. Drop a file on the box. The waveform appears.
- Set the change. Use a preset button, drag the sliders or type exact numbers. For tempo matching, enter the original and target BPM.
- Preview. Click the waveform to choose where to start, then press Preview result. Use Play original to compare.
- Download. Choose MP3 or WAV and click Process and download.
Why changing speed usually changes pitch
Sound is vibration, and pitch is how fast it vibrates. If you play a recording twice as fast, every vibration happens twice as often, so the pitch rises by an octave. That is how tape machines, record players and simple video speed controls behave. To change tempo without changing pitch, software has to make the audio last longer or shorter without changing the vibration rate of the sound itself.
The usual way is to cut the audio into small overlapping pieces, repeat or skip pieces, and blend them smoothly. This tool uses a waveform-similarity overlap-add method, often shortened to WSOLA. It looks for the best place to join each piece so that the waves line up, which avoids clicks and keeps speech and music natural. Pitch shifting combines the same stretch with a resample, so that the result has the new pitch and the old length.
Semitones, keys and cents
A semitone is the smallest step in Western music, such as from C to C sharp. Twelve semitones make an octave, which doubles the frequency. Each semitone multiplies the frequency by about 1.0595. A cent is one hundredth of a semitone, useful for fine tuning a recording that was slightly flat or sharp.
| Shift | Interval | Frequency ratio |
|---|---|---|
| +1 | Minor second | 1.059 |
| +2 | Major second | 1.122 |
| +3 | Minor third | 1.189 |
| +5 | Perfect fourth | 1.335 |
| +7 | Perfect fifth | 1.498 |
| +12 | Octave | 2.000 |
| -12 | Octave down | 0.500 |
To move a song from C major to D major, shift up two semitones. To make a song easier for a lower voice, shift down two or three. A recording made when A was tuned to 440 Hz and played against a modern track tuned to 442 Hz is about 8 cents off, which you can fix with the fine tune box.
Tempo, BPM and matching songs
BPM means beats per minute. If a song is 120 BPM and you play it at 125 percent, it becomes 150 BPM. Enter the original BPM and a target BPM, and the tool works out the speed for you. DJs use this to bring two tracks to the same tempo. If the pitch change is a problem, stay in Keep pitch mode so the key does not move.
| Speed | 120 BPM becomes | Typical use |
|---|---|---|
| 75% | 90 BPM | Learning a part |
| 90% | 108 BPM | Slower practice |
| 110% | 132 BPM | Warm-up pace |
| 125% | 150 BPM | Workout or nightcore |
| 150% | 180 BPM | Fast listening |
Practicing music and learning languages
Slowing a recording is one of the most useful practice tools. Reduce the speed to 70 percent, keep the pitch, and work out the notes or the lyrics. When you can play along, raise the speed in small steps, five percent at a time, until you reach the full tempo. For language learning, slow speech to 80 percent to hear each sound, then bring it back to normal speed.
Transcribers, singers and instrumentalists also use the pitch control. A guitar piece in a hard key can be lowered a semitone or two, and a vocal that is slightly too high can be transposed to a more comfortable range.
Getting the best sound quality
- Keep changes small when you can. A 10 to 20 percent speed change is nearly transparent.
- For big speed changes, use Linked (tape) mode if a pitch change is acceptable. It is the cleanest.
- Speech survives stretching better than drums. Percussive music may sound slightly smeared at 150 percent or more.
- Start with a high-quality source. Processing a low bitrate MP3 can magnify its flaws.
- Choose WAV if you will process the file again, and MP3 at 192 kbps or higher for the final version.
- Preview a section with the busiest part of the music, not just the intro.
Common uses
- Nightcore and slowed edits: a quick change of speed and pitch together.
- Podcasts and audiobooks: faster listening that keeps voices natural.
- Practice and transcription: slow, loopable material.
- Dance, fitness and DJ sets: tempo matched to a routine or another track.
- Karaoke: move a song into the singer's range.
- Sound design: make low, heavy or tiny versions of a sound effect.
Troubleshooting
- The result sounds warbly: the change is large. Reduce it, or use Linked (tape) mode.
- The voice sounds like a chipmunk: you are in Linked (tape) mode, or you raised the pitch. Switch to Keep pitch mode and set pitch to 0.
- The processing is slow: long files take longer. Close other tabs, or process a shorter section.
- The preview is silent: check your device volume, and click the waveform to choose a part of the file that has sound.
- The file will not open: your browser may not support the codec. Convert it to MP3 or WAV first.
Online tool or desktop software?
Desktop programs such as Audacity and professional workstations offer very high-quality stretching algorithms, formant preservation and automation of speed over time. They are the right choice for studio work. A browser tool is a better fit for quick jobs: a practice track, a faster podcast, a key change for karaoke. It requires no installation and does not upload your music.
Copyright reminder
Changing the speed or the key of a recording does not change who owns it. For private practice and study this is fine in most places. Sharing or publishing a sped-up or slowed version of a commercial song can require permission from the rights holders, even if the result sounds different. Use your own recordings, royalty-free music or music you have permission to modify.
Privacy and how it works
Your browser decodes the file into samples. The page then resamples and time-stretches them in memory with JavaScript, and encodes the result locally. Nothing is uploaded, stored or logged. The MP3 encoder library loads from a public CDN the first time you choose MP3, but your audio is not part of that request. Closing the tab clears the audio from memory.
Frequently asked questions
How do I speed up an MP3 without making it sound like a chipmunk?
Load the file, keep the mode on Keep pitch and set Speed above 100 percent, for example 125 or 150. The tool stretches time with a method that keeps the pitch the same. Preview 15 seconds to check, then download.
How do I slow down audio without changing the pitch?
Set Speed below 100 percent, such as 75 percent for practice or 50 percent for transcribing. The pitch stays the same because the tool uses time stretching instead of simply playing the audio slower.
How do I change the key of a song?
Set Pitch in semitones. Plus 2 raises the key by a whole tone, and minus 3 lowers it by a minor third. Speed stays at 100 percent in Keep pitch mode. Use Fine tune for small corrections in cents, where 100 cents is one semitone.
What is the difference between the two modes?
Keep pitch lets you set speed and pitch separately. Linked (tape) works like a tape or record player: faster is higher, slower is lower. The second mode is simpler and has no artifacts. It is also what makes nightcore and slowed edits.
What are nightcore and slowed versions?
A nightcore edit is a song sped up, typically 20 to 30 percent, with the pitch rising along with it. A slowed edit is the opposite: slower and lower. Use the Nightcore and Slowed buttons for a quick start. We do not add reverb or effects.
Will the quality get worse?
Linked (tape) mode uses resampling and is very clean. Keep pitch mode uses time stretching, which can add slight warbling or a loss of punch at large changes, especially on drums and dense music. Changes within about 25 percent usually sound natural.
What are the limits on speed and pitch?
Speed ranges from 25 to 400 percent and pitch from minus 12 to plus 12 semitones, plus 100 cents of fine tuning. Results are best between 50 and 200 percent. At extreme settings any time stretcher produces artifacts.
Can I match the tempo of two songs?
Yes. Enter the song's original BPM and the BPM you want in Target BPM. The speed is set for you. If you do not know the BPM, use the BPM Detector tool.
Is my audio uploaded to a server?
No. The file is decoded and processed on your device. The page downloads an open-source MP3 encoder from a public CDN the first time you choose MP3, but your audio is never sent anywhere.
What does the preview do?
It processes 15 seconds starting from the point you click on the waveform, so you can hear the result in a moment before processing the whole file. Click Play original to compare.
How long does processing take?
Linked (tape) mode is nearly instant. Keep pitch mode on a four minute song usually take a few seconds on a modern computer. A progress bar shows the status.
Does it work on podcasts and audiobooks?
Yes. Speeding speech up to 125 or 150 percent with the pitch kept is a common way to listen faster. Speech tolerates time stretching well.
Can I use it to learn a song or practice an instrument?
Yes. Slow the track to 70 or 80 percent and keep the pitch, loop it in your player, and raise the speed as you improve. You can also shift the key to suit your voice or a capo position.
Can I change the speed of a video's audio?
You can process the audio track of a video file and download it as audio. The tool does not output video.
Does it work on a phone?
Yes, in a modern browser. Very long files may need more memory than a phone has.
Which formats can I open and save?
You can open MP3, WAV, M4A, OGG, FLAC and audio from many video formats, as long as your browser supports them. You can save MP3 or WAV.
What can I print or save from the page?
Print / save summary prints the settings and the waveform, and Copy summary copies the settings as text. The processed audio is the main download.
Sources and further reading
- Verhelst, W. and Roelands, M. (1993). An overlap-add technique based on waveform similarity (WSOLA) for high quality time-scale modification of speech. IEEE ICASSP.
- ISO 16:1975, Acoustics: Standard tuning frequency (Standard musical pitch), which sets A4 at 440 Hz.
- MDN Web Docs, AudioBufferSourceNode.playbackRate, for how speed and pitch are linked in simple playback.
- Müller, M. (2015). Fundamentals of Music Processing, Springer, for time-scale modification and pitch shifting.
- LAME project and the lamejs encoder, the open-source MP3 encoder used for MP3 output.
Sources were consulted in October 2026. Standards and rules can change, so always check the official page for your situation.