Free Audio Pitch Shifter

Worked example

Open a 3-minute stereo song, song.mp3, recorded at 44.1 kHz in the key of A, that you want in C. Under "Song's key" choose A, then choose C under "Target key". The "Pitch shift (semitones)" slider moves to +3 by itself and the line below reads "+3 semitones (frequency ×1.189) · A → C". "Mode" stays on "Pitch only (keep tempo)". Press "▶ Play shifted" to hear 8 seconds from the "Start at" point, then "▶ Play original" to compare. With "WAV" selected, press "Shift pitch". "Shifting pitch…" counts to 100%, and the page shows "✓ WAV · 30.3 MB", a player and a "Download" button. The file is named song_pitch+3.wav. The size is expected: 16-bit audio, 2 channels, 44,100 samples a second, for 180 seconds.

Which settings to use, and the limits

• Pick the keys instead of counting semitones. Under "Song's key" choose the key your song is in. A "Target key" box appears; choose the key you want and the "Pitch shift (semitones)" slider moves for you. The tool takes the shortest way, never more than 6 semitones, so A to C is +3, not −9. Keys are listed with sharps (C♯, D♯, F♯, G♯, A♯). The slider itself runs from −24 to +24, and the quick presets are −12, −5, −2, −1, +1, +2, +5 and +12. The tool does not detect your song's key; you set it.
• Choose "Pitch only (keep tempo)" or "Pitch + speed together". "Pitch only" keeps the length by time-stretching first and then resampling. The page says large shifts can add some artifacts and that moderate shifts (±5 semitones) sound best. "Pitch + speed together" is a plain resample, like a tape played faster or slower. The page says it has no artifacts, but the length changes: at +4 the line "Plays at 1.26× speed" appears. The "Slowed" preset is −4 semitones and "Nightcore" is +4, and both switch to the speed mode for you.
• Fine-tune with cents. The "Fine-tune (cents)" box takes −100 to +100 in steps of 1, and 100 cents is one semitone. The hint says about −32 cents retunes 440 Hz to 432 Hz. The total shift is the semitones plus cents divided by 100, so +2 semitones and −32 cents is +1.68, and the line shows "+1.68 semitones (frequency ×1.102)". A blank box counts as 0, a value beyond ±100 is treated as ±100, and choosing a target key resets the cents to 0.
• Preview a slice before you render. Set "Preview length" to "8 seconds", "30 seconds" or "To the end" (the default is 8 seconds), and move "Start at" in one-second steps to choose where the slice begins. "▶ Play shifted" processes only that slice, so it starts quickly; "▶ Play original" plays the same slice untouched. The page says "Press play again after changing the shift." "▶ Play shifted" stays disabled while the total shift is zero. A preview is not saved or downloaded.
• Pick WAV, MP3 or M4A. WAV is written straight away as 16-bit audio, at the file's own sample rate when it can be read from the file header and at your device's rate otherwise, but the file is large. MP3 and M4A are encoded at 192 kbps and need a one-time encoder download of about 30 MB, which the page notes beside "Output format". Your choice is remembered in the browser. On a touch screen with nothing saved it starts on MP3, otherwise on WAV. The download is named like song_pitch+3.wav or song_speed-4.mp3.
• Know the file limits. The tool takes one file at a time, audio or video. It refuses a file above about 2 GB on a normal computer, 1 GB on a computer reporting 4 GB of memory or less, and 400 MB on a phone or tablet. The whole file is decoded into memory before anything plays, so a long file needs far more memory than its size on disk. The encoder is fetched only for MP3 and M4A. Your audio is shifted in the browser and is not uploaded.

Common problems and how to fix them

It says "Could not process this audio file. It may be an unsupported or corrupted format."

This appears when decoding or the pitch shift fails after you press "Shift pitch". Your browser's own decoder has to open the file, so rare or damaged formats fail. The file is decoded as soon as you add it, but a failure at that point is silent and only shows when you press "Shift pitch" or a preview button. Convert the file to MP3 or WAV, or copy the original again, and add it.

It says "Could not play the preview. This audio format may be unsupported."

This is the same decoding problem, raised from "▶ Play shifted" or "▶ Play original" instead of the render. Try another copy or format of the file. If the preview plays but the render fails later, the problem is in the render step, so read the message that the render shows.

It says "The pitch shift worked, but the MP3 encode failed. Try again, or switch the output format to WAV." (or M4A, whichever you chose)

The shift finished but the MP3 or M4A encoder failed, either while loading its download of about 30 MB or while encoding. The shifted audio is not kept, so pressing "Shift pitch" again repeats the shift. Choose WAV under "Output format", which needs no encoder.

It says "This file is 2.6 GB, which is over the ~2 GB this device can process in the browser. Try a smaller file or a shorter clip."

The size check runs when you add the file, before any decoding. The numbers are your file and your device's limit: about 2 GB, 1 GB or 400 MB as listed above. This tool only blocks; it has no softer caution level for large files. Use a shorter clip, or a desktop computer if you are on a phone.

"Shift pitch" and "▶ Play shifted" are greyed out, and the page says "Pick a preset or move the slider to choose a pitch shift."

Both buttons are disabled while the total shift is exactly zero, because there is nothing to change. The total is semitones plus cents, so +1 semitone with −100 cents is also zero. Pick a preset, move the slider, or choose a different target key. "▶ Play original" still works at zero.

How it compares

This tool shifts a whole file in the browser, in one of two ways. "Pitch only (keep tempo)" time-stretches and then resamples, so the length stays the same, but large shifts can sound processed. "Pitch + speed together" is a plain resample, which is what slowing down or speeding up a record does. It has no formant control, no key detection, no batch mode and no way to shift only part of a file, and MP3 and M4A are fixed at 192 kbps. A digital audio workstation or a dedicated pitch plug-in offers more control. In exchange there is nothing to install, and the preview lets you settle the shift before you render.