Pitch Shift in Audacity: Change the Key of a Song Without Changing the Tempo
· 9 min read
Dominic Mazzoni and Roger Dannenberg started Audacity at Carnegie Mellon University in the autumn of 1999, under the name CMU Visual Audio. Version 0.8 went public on 28 May 2000. Change Pitch, the effect that moves a selection up or down without changing its length, has been in the Effect menu since the 1.x series, and its high quality mode uses SBSMS, the stretching engine Clayton Otey wrote for Sliding Stretch. Muse Group, the owner of MuseScore and Ultimate Guitar, took over the trademark in April 2021. Audacity 3.4 (2 November 2023) added time stretching on the clip, Audacity 3.5 (22 April 2024) added a pitch shift on the clip, and Audacity 4.0.0 (3 September 2026) rebuilt the interface on Qt and kept both. If the unit is new, what a semitone is covers the step the page counts in.
If the backing track is on your computer, hear CountIn count it in on beat one. Listening is free and needs no account.
Two ways to move the key
| Change Pitch effect | Clip pitch dialog | |
|---|---|---|
| In Audacity since | the 1.x series | 3.5, 22 April 2024 |
| Where | Effect > Pitch and Tempo > Change Pitch, with audio selected | right-click the clip, or its ⋯ menu > Open pitch and speed dialog; Alt+Up or Alt+Down moves one semitone |
| Unit | note names, semitones, cents, Hz or per cent, all linked | semitones and cents |
| Writes into the audio | yes, the waveform changes (Undo reverses it) | no, the clip plays shifted and is rendered at export |
| Length of the selection | kept only with Use high quality stretching (slow) | kept |
| Option for singing | none | Optimize for voice |
| Shows the shift afterwards | nowhere | a badge on the clip |
The Audacity 4 manual on the Pitch and Tempo group: "you can raise the pitch without speeding the audio up, fit a recording to a new length without changing the key, or move both together the way a tape machine would."
Change Pitch, control by control
The dialog opens with an Estimated start pitch line: the note, octave and frequency Audacity measured at the start of the selection. The fields under it are one shift written four ways, and the manual says "all three views stay in step with each other".
| Control | What it holds | From the manual |
|---|---|---|
| From pitch, To pitch | note name and octave at the start, note name and octave at the end | "If you know both the key the original recording is in and the key you want to change it to, change both the Pitch 'from' and 'to' values." |
| Semitones (half-steps) | the shift as a whole number, minus for down | "If you do not know the key the original recording is in but you know how many semitones it needs to be changed, enter that value here." |
| Cents | the fraction of a semitone, in hundredths (Audacity 4) | "the remaining fraction of a semitone, in hundredths" |
| From frequency, To frequency | the same shift in Hz | "Detection of a steady sine tone will often be very accurate" |
| Percent Change | slider and field | "4 semitones upwards is equivalent to 25.992%" |
| Use high quality stretching (slow) | the SBSMS algorithm from Sliding Stretch | "the exact length of the selection will be preserved" |
The steps, Audacity 4 and Audacity 3
| Step | Audacity 4 | Audacity 3 |
|---|---|---|
| 1. Open the song | File > Import > Audio, or drop the file on the window | the same |
| 2. Select it | click the clip header, or Ctrl+A (Cmd+A on a Mac) | click in the track, Ctrl+A |
| 3. Open the effect | Effect > Pitch and tempo > Change pitch | Effect > Pitch and Tempo > Change Pitch |
| 4. Type the shift | Semitones: 2 for a whole step up, -3 for a minor third down | the same field |
| 5. Keep the length | tick Use high quality stretching (slow) | the same box |
| 6. Listen | Preview, then Apply | Preview, then Apply |
| 7. Export | File > Export > Audio: WAV, MP3 or FLAC | File > Export Audio |
| Clip pitch dialog (3.5 and later) | |
|---|---|
| One semitone up or down | select the clip, Alt+Up or Alt+Down |
| An exact value | right-click the clip, Open pitch and speed dialog, type semitones and cents |
| A sung part | tick Optimize for voice; the manual: it "preserves vocal resonances when shifting speech or singing" |
| Where the shift shows | a badge in the clip's top corner |
| When it is written | at export; the project keeps the unshifted audio |
The Export Menu page of the Audacity 4 manual: exporting mixes the tracks "as playback would, applying each track's volume, pan and effects", and "the project itself, with its separate tracks, clips and effects, is left exactly as it was".
Traps the manual names
| Trap | What happens | From the manual |
|---|---|---|
| The detected note is read as the key | the From pitch field holds the first loud note, not the key | "These two controls are not a detection of the 'key' or 'tonality' of music." (Audacity 3) |
| Wrong octave in the estimate | every other field is measured from it | "on material that is not a clear sustained note it can land on the wrong octave" (Audacity 4) |
| Note names without the octave | A to C#/Db with both octaves at 4 reads as 8 semitones down; the manual's example moves the To octave to 5 by hand | "the octave number always increases by 1 when moving up through C" |
| Length after the effect | the selection is not exactly as long as before unless the high quality box is ticked | "Change Pitch by default does not keep the length of the selection exactly as before." |
| Detection ceiling | the estimate is unreliable above one eighth of the sample rate | "for the default project sample rate of 44100 Hz, detection will not be accurate much above 5500 Hz" |
| Large shifts | artefacts on transients | "a smeared or watery quality on transients. Small corrections are usually clean; anything drastic is a creative effect rather than a repair." |
Semitones in per cent
Every semitone is the same ratio, the twelfth root of two, so the Percent Change field grows faster than the semitone count.
| Semitones | Up | Down |
|---|---|---|
| 1 | +5.946% | -5.613% |
| 2 | +12.246% | -10.910% |
| 3 | +18.921% | -15.910% |
| 4 | +25.992% | -20.630% |
| 5 | +33.484% | -25.085% |
| 6 | +41.421% | -29.289% |
| 7 | +49.831% | -33.258% |
Listening results on full backing tracks, shift by shift, are in how to change the key of an MP3; the number of semitones between two keys is in the transposition chart published next.
Audacity and the song key changer, side by side
A backing track for a singer usually needs two changes before the gig: the key, and a count-in on beat one in the same file. Audacity's metronome, Rhythm Track, runs at a fixed tempo and is lined up against the song by hand; the procedure is in the Audacity click track and count-in guide. The song key changer on this site is the one-pass version of both.
| Audacity Change Pitch | Song key changer | |
|---|---|---|
| Runs | installed, Windows, macOS, Linux | in the browser, no install |
| Shift | any number of semitones, cents, Hz or per cent | up to 7 semitones either way |
| Tempo | unchanged | unchanged |
| Count-in on beat one | Rhythm Track, aligned by hand | found and baked in |
| Hear the result first | Preview in the dialog | the free preview plays the whole song in the new key with the count-in |
| Output | WAV, MP3, FLAC and the libsndfile formats | MP3 or WAV |
| Price | free, GPLv3 | preview free, export with a plan |
Frequently asked questions
How do I change pitch in Audacity without changing speed?
Effect > Pitch and Tempo > Change Pitch, with the audio selected, then a value in Semitones (half-steps). The effect leaves the tempo as it was. From Audacity 3.5 (22 April 2024) a selected clip also shifts with Alt+Up and Alt+Down, one semitone per press.
How many semitones can I shift a song in Audacity?
The dialog takes any value. The manual's limit is about quality, not range: "Small corrections are usually clean; anything drastic is a creative effect rather than a repair." The per cent table above gives the ratio for each step up to 7.
Does Audacity detect the key of a song?
No. The Estimated start pitch is the first detectable note of the selection, and the Audacity 3 manual says the From and To controls "are not a detection of the 'key' or 'tonality' of music".
Where is Change Pitch in Audacity 4?
Effect > Pitch and tempo > Change pitch, next to Paulstretch and Sliding Stretch. The clip menu has Open pitch and speed dialog. Audacity 4.0.0 was released on 3 September 2026, 4.0.1 on 30 September and 4.0.2 on 2 November 2026.
Is the clip pitch shift the same as Change Pitch?
Both keep the tempo. The clip dialog keeps the clip length, adds Optimize for voice and writes nothing until export; Change Pitch also takes note names, Hz and per cent and changes the waveform when applied.
Can Audacity change key and tempo together?
In Audacity 3, Effect > Pitch and Tempo > Change Speed and Pitch moves both at once. In both versions Sliding Stretch takes a starting and a finishing value for tempo and for pitch, in semitones or per cent, and slides between them across the selection.
Sources
- Audacity 4 Manual: Change Pitch, Pitch and Tempo, Trim and stretch, Export Menu, Audacity 3 to 4 transition guide (last updated 9 November 2026).
- Audacity 3 Manual: Change Pitch, Sliding Stretch (manual.audacityteam.org).
- Audacity blog: Audacity 3.4 (2 November 2023), Audacity 3.5 (22 April 2024).
- Audacity changelog: 4.0.0 (3 September 2026), 4.0.1 (30 September 2026).
- Wikipedia: Audacity (audio editor), project history 1999 to 2026.
If the backing track is on your computer, hear CountIn count it in on beat one. Listening is free and needs no account.
← Back to Blog · Click track · Free BPM finder · Tap tempo · Key changer