Change Audio Pitch

Shift audio pitch in your browser

Pick an audio file and how many semitones to move it: positive values raise the pitch, negative values lower it, and the speed stays exactly the same. Use it to transpose a backing track into a singable key, deepen a voice recording, or make the classic chipmunk / slowed-and-deep effects without touching the tempo. Drag the slider for whole semitones, type a decimal for cent-level fine-tuning, or hit one of the preset chips. The shift runs entirely in your browser with ffmpeg compiled to WebAssembly, so your audio is never uploaded to a server.

Worked example

Transpose a backing track up a whole step (D to E): upload the track, set Semitones to 2, leave Format on mp3, and run. The result plays in the new key at the original tempo and downloads as the original name with a -pitch-shifted.mp3 suffix. Some more common shifts:

• 12 — one octave up (a 440 Hz A becomes an 880 Hz A).
• -12 — one octave down.
• -3 — lower a song three semitones into a more comfortable vocal range (a common karaoke trick when the original is too high).
• 1 — raise a recording made in E♭ tuning back to standard pitch, so you can play along without retuning your guitar. -1 does the reverse.
• 0.5 — a quarter-tone nudge (50 cents) for tuning mismatches; one cent is 0.01, so tuning an A=432 Hz recording up to A=440 Hz is about 0.32 semitones (and -0.32 converts 440 Hz music down to 432 Hz).

Semitone cheat sheet

Count piano keys, black keys included — each key is one semitone. Moving from C to D is 2, C to E is 4, down a perfect fourth is -5, and any octave is 12. So a song in G that you want in E goes down -3; a song in C that you want in D goes up 2. Producers use the same counting to layer harmonies: a copy of a vocal shifted 3, 4, 5, or 7 semitones lands on the classic harmony intervals.

How it works

The tool uses the classic resample method, fully offline: the audio is resampled to a new rate (which shifts pitch and speed together, like changing tape speed), then time-stretched back to the original duration with ffmpeg's atempo filter. Each semitone is a frequency change of about 5.95% (the twelfth root of 2), and fractional shifts are computed with the same formula. Pitch accuracy is within a fraction of a cent, and the output duration matches the input.

Formats

• MP3 — lossy at 192 kbps; small and playable everywhere (the default).
• WAV — lossless 16-bit PCM; largest, ideal for further editing.
• OGG — lossy Vorbis at 192 kbps; open format, good quality per byte.
• FLAC — lossless and compressed; smaller than WAV, still a perfect copy.
• M4A — AAC in an mp4 container; good quality at small sizes.

Limits and edge cases

• Input files up to 10 MiB; anything ffmpeg can decode works (mp3, wav, flac, m4a/aac, ogg, opus, and most video containers' audio tracks).
• Shifts are limited to ±24 semitones (two octaves). Large shifts sound increasingly processed — time-stretching artifacts (a slight metallic or fluttery quality) grow with the shift size; within ±5 semitones they are hard to hear on most material.
• 0 semitones is rejected as a no-op rather than silently re-encoding your file — use the audio-convert tool if you only want a format change.
• The output is always re-encoded (the filter chain requires it) and resampled to 44.1 kHz, the CD-standard rate most music already uses.
• Everything in the mix shifts together — this transposes the whole track, it cannot re-tune one instrument or correct a single off-key note.

FAQ