Audio

Audio Speed & Pitch Changer

Speed audio up or slow it down (0.25×–4×) while keeping pitch, shift pitch ±12 semitones at the same speed, or link both vinyl-style.

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About this tool

Audio Speed & Pitch Changer re-encodes an audio file at a new speed. Drop in MP3, WAV, M4A, OGG or FLAC and set a speed multiplier from 0.25× to 4× in 0.05 steps. With the pitch slider at 0, speed changes keep the original pitch using ffmpeg's atempo filter, chained for values outside 0.5–2×. Tick 'Link speed & pitch' for vinyl-style behaviour: the audio is played back at a different sample rate (asetrate + aresample), so faster also means higher, and the pitch slider is ignored. The pitch slider shifts the key from -12 to +12 semitones at the speed you set: the audio is resampled to 44.1 kHz, its sample rate is reinterpreted (asetrate) to raise or lower the pitch, and atempo stretches it back to the requested speed, so pitch and linked results come out at 44.1 kHz. Pick MP3, WAV, OGG or M4A output (lossy formats at 192 kbps), preview, and download. Everything runs locally via ffmpeg.wasm — files never leave your device.

Why use it

  • Change speed from 0.25× to 4× while keeping the original pitch

  • Vinyl-style linked mode for classic turntable-feel pitch up/down

  • Chained atempo filters cover the full speed range in one pass

  • 100% browser-side — files never leave your device

  • Free, no watermark, no signup, no daily cap

  • Inline preview before you download

How to use

  1. Click or drag your audio file onto the upload area.
  2. Set the speed slider — 1.00× = unchanged, below 1 = slower, above 1 = faster.
  3. Move the pitch slider to shift the key by up to 12 semitones either way; the speed you set stays the same.
  4. Optionally tick 'Link speed & pitch' for vinyl-style behaviour — the speed slider then sets pitch too and the pitch slider is ignored.
  5. Pick an output format and click 'Process & Download'.
  6. Audition the result in the inline player, then download.

When it helps

  • Slowing a guitar solo to half speed (without changing key) for transcription
  • Speeding up a podcast 1.25× without chipmunk-pitch artifacts
  • Slowing a spoken-language lesson to catch every word
  • Pitching a sound effect up or down with linked vinyl mode
  • Vinyl-style speed-up effect (DJ-style pitching) on a sample
  • Creating a slowed + reverb-style fan edit (combine with a reverb plugin)

Examples

Transcribe a guitar solo

Input

MP3 of solo at 1.00× speed

Expected result

MP3 at 0.5× speed, same key — slow enough to learn note-by-note

Faster podcast

Input

M4A episode at 1.00×

Expected result

M4A at 1.25× speed, original pitch — finish faster, no chipmunk

Vinyl pitch-down

Input

Track with Link speed & pitch ticked and speed set to 0.95×

Expected result

Track about 5% slower and about 0.9 semitone lower, like a DJ slowing the platter

Tips

  • atempo is chained in 0.5× / 2× steps, so the full 0.25×–4× range works in a single pass.
  • Linked mode = vinyl: a speed of 0.95× is about 5% slower and about 0.9 semitone lower. The pitch slider has no effect while Link is ticked.
  • To change key without changing tempo, leave the speed at 1.00× and move only the pitch slider.
  • Slowing audio to half speed roughly doubles the file length (and the file size for lossless outputs).

Frequently Asked Questions

Can I adjust speed without changing pitch?
Yes — that's the default with the pitch slider at 0. atempo time-stretches without affecting pitch.
Can I change pitch without changing speed?
Yes — leave the speed slider at 1.00× and move only the pitch slider. asetrate and aresample shift the pitch, and a compensating atempo pass returns the audio to its original speed.
What's the difference between linked and unlinked?
Unlinked: speed changes keep the pitch. Linked: the speed slider changes the playback rate like a turntable, so speeding up raises pitch; the pitch slider is ignored.
Why is the maximum 4× speed?
Beyond about 4×, atempo artifacts (transient smearing) become very obvious. Higher values are theoretically possible but don't sound musical.
Does this use any AI or fancy pitch correction?
No — it uses ffmpeg's classic time-domain time-stretch (atempo) and sample-rate-based pitch shift. Works for most material; very large pitch shifts will sound artificial.
Will the file size change?
Yes. Slowing audio makes it longer (bigger file at the same bitrate); speeding up makes it shorter.
Are my files uploaded?
No. ffmpeg.wasm runs locally in your browser; the file never leaves your device.
Why do extreme pitch shifts sound 'chipmunky' or 'demonic'?
asetrate-based pitch shifting also stretches formants. Real instruments and voices have pitch-independent formant structure; without formant correction, big shifts sound unnatural.

Explore the category

Audio Compressor Shrink MP3, WAV, M4A, OGG and FLAC files by re-encoding at a lower bitrate. Choose 32–320 kbps, pick MP3, OGG or M4A output, then download. 100% browser-side via ffmpeg.wasm. MP3 Converter Convert audio between MP3, WAV, OGG, M4A and FLAC in your browser. Choose bitrate or sample rate, then download. Runs locally via ffmpeg.wasm — no uploads. Normalize Audio (LUFS) Normalize loudness of MP3, WAV, M4A, OGG and FLAC files using ffmpeg loudnorm (EBU R128). Hit Spotify, podcast or broadcast targets — runs locally via ffmpeg.wasm. Audio Reverser Reverse any audio file so it plays backwards. Drop MP3, WAV, M4A, OGG or FLAC, choose output format, and download. ffmpeg.wasm areverse — no upload. Audio Merger Concatenate multiple MP3, WAV, M4A, OGG or FLAC files into one continuous audio track. Reorder with ↑ / ↓ buttons, set output format and bitrate, then download. MP3 Cutter & Audio Trimmer Trim or cut uploaded audio with draggable waveform handles, precise preview, undo, and exports to WAV, MP3, M4A, OGG, or FLAC.
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Glossary

atempo
ffmpeg audio filter that changes playback speed without changing pitch. This tool chains it in 0.5× / 2× steps to cover 0.25×–4×.
asetrate
ffmpeg filter that changes the sample rate metadata, scaling pitch and tempo together.
aresample
ffmpeg filter that resamples audio back to a target sample rate. Used after asetrate to normalise the output.
Semitone
A musical interval — 12 semitones make an octave. +1 semitone is a small upward pitch shift; +12 doubles the pitch.
Time-stretching
Changing audio speed without changing pitch. Achieved here via atempo.
Pitch-shifting
Changing audio pitch without changing speed. This tool's semitone slider uses asetrate + aresample but does not yet hold the speed constant.
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