Pitch Changer (Pitch Shifter and Key Changer)

What the pitch changer does

This tool moves every note in a recording up or down by a chosen interval while keeping the length of the piece the same. The main control counts in semitones, from minus 12 to plus 12, which is one octave in either direction. A second control, fine tune, adds or subtracts up to 50 cents, half a semitone, for adjustments too small to hear as a different note.

The most common reasons to reach for it are practical. A singer needs a karaoke or rehearsal track in a more comfortable key. A guitarist who tunes a half step down wants a backing track that matches. A producer needs a sample to sit in the key of a project. A DJ wants two tracks to share a key. A person recording a voiceover wants a slightly deeper or lighter voice. Each of these is a small, deliberate shift, not a special effect.

The tool starts at plus 2 semitones. It works only with audio files you already have, so there is no link box and no fetching from streaming services. Use material you made or may edit.

How semitones and cents work

A semitone is the smallest step on a piano: the distance between two neighboring keys, white or black. Twelve of them make an octave, which doubles the frequency. Because the steps are equal in ratio rather than equal in hertz, each semitone multiplies every frequency by the twelfth root of two, about 1.0595. The table in the Numbers tab gives the ratio for common steps and shows where A at 440 Hz lands.

A cent is one hundredth of a semitone, a ratio of roughly 1.00058. Many listeners notice a difference of roughly 5 to 10 cents when two tones sound together, and a smaller difference as slow beating. That makes cents the right unit for matching a track to an instrument that is slightly out of tune, or for correcting a recording made at A equals 432 or 442 against one at 440. Moving from 440 to 442 is about 7.8 cents; to 432, about minus 31.8.

To choose how many semitones, think about the key rather than the ratio. If a song is in C major and you move it up two semitones, it lands in D major. The last column of that table lists where a piece in C major ends up for each step, and the same distances apply to any other key.

Presets and what each one is for

The presets cover the moves people make most. Minus 2 and plus 2 are a whole step, the usual adjustment for fitting a vocal range. Minus 1 and plus 1 are half steps, which matter for guitarists who tune down by that amount or for matching a sample that is just next door to the key you want.

Octave up and Octave down jump by twelve semitones. Up gives a thin, bright, almost toy-like sound; down gives a deep, heavy one. Both are most useful on single instruments or sound effects, not whole mixes, since voices move far from natural at that distance.

After picking a preset you can turn the Semitones or Fine tune knob; the preview refreshes in about a quarter second, and a double-click on a knob sends it back to its default. A practical habit is to listen for the vocal first, then the bass: a vocal that sits comfortably but a bass that has gone flabby suggests trying one semitone less. If you reach a setting worth keeping, Copy settings link puts the values in the address so you can bookmark or share it.

Finding the right key for a voice

Every singer has a comfortable range, and a track written for a different voice may sit just out of reach. The simplest test is to sing the highest and lowest notes of the melody against the original. If the top is a strain, lower the track one semitone at a time until the high note feels easy; if the low notes disappear into a mumble, raise it instead. A shift of one to three semitones solves most mismatches.

Keep in mind that going lower moves the whole accompaniment down as well, so a bass line may turn muddy. Going higher can make the guitar or piano feel brighter and thinner. If the original key is unknown, the key finder can estimate it, and the Camelot wheel shows which keys sit next to it.

For a duet or a group, choose the key that suits the most limited voice. A semitone either way is rarely noticed by an audience but can decide whether someone sings with comfort or with tension.

How a pitch shifter works

Changing the speed of a recording changes its pitch, and the other way around, so a pitch shifter has to separate the two. This tool does it in two stages. It first stretches or squeezes the audio in time so that the length becomes what the final pitch needs, then resamples it, which brings the length back to the original while moving every frequency by the chosen ratio. The net result is a new pitch at the old tempo.

For the full story of how the time-stretch stage works, and why it differs from simply playing a file faster or slower, see the audio speed changer page; that explanation lives in one place so it does not need repeating here.

What matters for you is the outcome. Small shifts of a few semitones sound clean on most material. Larger shifts pile up more processing, and that is where the sound starts to show its seams.

Artifacts, formants and how far to go

A voice is shaped by resonances of the throat and mouth, known as formants, which give it a recognizable character. When you shift pitch this way, the formants move along with the notes, so raising a voice by many semitones makes it sound smaller, closer to a child or a cartoon, and lowering it makes it sound larger and heavier. The tool does not keep formants fixed on their own, so it does not keep the same singer's timbre at large shifts.

Beyond roughly five semitones in either direction, other artifacts become easier to notice: a slight metallic or watery shimmer, softened drum attacks, and a loss of natural air around vocals. Within two or three semitones, most music still sounds natural. If you need a big move, try two smaller ones in separate passes, or consider re-recording the part.

Complex dense mixes show artifacts earlier than a solo instrument. A bare piano, an acoustic guitar or a single voice usually tolerates a wider range than a full band. Always compare Result and Original with headphones at a moderate level.

Matching keys for DJs and producers

For mixing two tracks harmonically, find the key of each, then shift one by the number of semitones that separates them. A move of one or two semitones can turn a clash into a smooth blend. The cents control helps when a track was recorded slightly off standard tuning and sounds sour against a sampled loop even at the same nominal key.

If the tempos also differ, change the speed in a separate step so the two jobs stay clear. Because the pitch change does not alter the length, the beat grid of the original remains intact, which keeps loops aligned in a project.

A good workflow, repeated for each track, is to shift in small steps, listen with the other track playing, and save a copy of each attempt. File names carry the tool name, so they are easy to tell apart.

When a track was made in a tuning that is not 440 Hz, a fine tune of a few cents is often all it takes to make it agree with a keyboard or sampler. Listen to a sustained note from both sources at once; slow wobbling means they are still a few cents apart, and steady blending means they match.

Formats, limits and privacy

MP3, WAV, M4A, AAC, Ogg, Opus, FLAC and anything else your browser can open will load, to a maximum of 250 MB. Output choices are MP3 (four bitrates between 128 and 320 kbps) or WAV (16 or 24 bits). Pick WAV if more processing is coming, because each lossy save discards a bit of detail. Most MP4, MOV and WebM videos open too, so you can shift the key of a rehearsal filmed on a phone and keep the audio as MP3 or WAV.

The shifting is carried out by your own device, so the recording goes nowhere. The last file you opened stays in your browser on this device, giving other tools a shortcut; clearing the site data removes it. The links beneath the player forward the shifted audio through local storage. Under the drop zone, a small note spells out that only audio files you have can be used and links from streaming sites cannot be opened.