Pitch is how high or low a note sounds, measured in hertz or semitones. Tempo is how fast the music moves, measured in beats per minute (BPM). They are independent: a song can get faster without getting higher. They move together only when audio is sped up like a tape or record, where 12 % faster sounds 2 semitones higher.
To change them separately, or together on purpose, use the Pitch and Tempo Changer: one control for semitones, one for speed or a target BPM, and a “linked” switch for the record effect. Below: a side-by-side table, why speed changes pitch, a speed-to-pitch reference and measured results.
Pitch vs tempo side by side
| Pitch | Tempo | |
|---|---|---|
| Describes | How high or low a sound is | How fast the beat goes |
| Unit | Hz (A4 = 440 Hz); semitones and cents | BPM (beats per minute) |
| Typical change | ±1–5 semitones to fit a voice | 75–90 % to practise; 105–125 % for energy |
| Changes the key? | Yes, by whole semitones | No |
| Changes the song length? | No (with a pitch shifter) | Yes: 80 % speed makes 3:00 last 3:45 |
| Changes the rhythm pattern? | No | No, only how fast it is played |
| Problem it solves | Song too high or too low for your voice | Passage too fast to learn or play |
| Tool | Pitch Shifter or Online Key Changer | Pitch and Tempo Changer (speed %, target BPM) |
Pitch, tempo, rhythm and volume
These four are often mixed up in school questions. Pitch is highness or lowness; tempo is the speed of the beat (“the fastness or slowness of music is called tempo”); rhythm is the pattern of long and short notes; volume (loudness) is how strong the sound is, in decibels. If a musician wants a song faster or slower without altering the notes, the element to adjust is the tempo.
Tempo vs speed vs BPM
Tempo is the musical speed, and BPM is its unit: “a tempo of 120 BPM”. Playback speed is a percentage of the original: a 120 BPM song played at 80 % speed has a tempo of 96 BPM. “Speed” in audio apps often means the tape-style change that moves pitch too, so check which one an app uses.
Does tempo change pitch? Why speeding up raises the pitch
Changing the tempo does not change the pitch, as long as the tool uses time-stretching. It does change the pitch when the audio is simply played faster or slower. A sound wave repeats a fixed number of times per second; play the recording 12.25 % faster and every cycle arrives 12.25 % sooner, so every frequency rises by the same factor: 440 Hz becomes 493.88 Hz, exactly 2 semitones higher. That is why a record played at 45 rpm instead of 33⅓ rpm (×1.35) sounds about 5.2 semitones higher, and why slowed tapes sound deep.
The formula is the same in both directions: semitones = 12 × log2(speed ratio), and speed ratio = 2^(semitones ÷ 12). Modern tools break this link with time-stretching and pitch scaling: the audio is cut into short overlapping pieces that are re-spaced in time (tempo) or resampled and re-spaced (pitch), so one can move without the other. That is how you change the pitch without changing the speed, or the tempo without the pitch.
Speed vs pitch reference table
What a tape-style (linked) speed change does to pitch, tempo and length. With a time-stretching tool the pitch column becomes 0 and only the tempo and length change.
| Playback speed | Pitch change in semitones (linked) | In cents | 120 BPM becomes | A 3:00 song lasts |
|---|---|---|---|---|
| 50 % | −12.00 | −1200 | 60.0 BPM | 6:00 |
| 75 % | −4.98 | −498 | 90.0 BPM | 4:00 |
| 80 % | −3.86 | −386 | 96.0 BPM | 3:45 |
| 89.09 % | −2.00 | −200 | 106.9 BPM | 3:22 |
| 90 % | −1.82 | −182 | 108.0 BPM | 3:20 |
| 94.39 % | −1.00 | −100 | 113.3 BPM | 3:11 |
| 105.95 % | +1.00 | +100 | 127.1 BPM | 2:50 |
| 110 % | +1.65 | +165 | 132.0 BPM | 2:44 |
| 112.25 % | +2.00 | +200 | 134.7 BPM | 2:40 |
| 125 % | +3.86 | +386 | 150.0 BPM | 2:24 |
| 150 % | +7.02 | +702 | 180.0 BPM | 2:00 |
| 200 % | +12.00 | +1200 | 240.0 BPM | 1:30 |
Two rows worth remembering: 94.39 % and 105.95 % are exactly one semitone down and up, and 50 % / 200 % are one octave. Each semitone is a 5.95 % step in speed. For semitone maths between notes, the semitone calculator does the counting; what semitones are explains the 12 steps.
Measured: one test file, five changes
We ran a 12-second test file (left channel: a 440 Hz tone; right channel: clicks at 120 BPM) through the Pitch and Tempo Changer and measured each download: frequency of the tone, spacing of the clicks, and file length.
| Setting | Tone (was 440 Hz) | Tempo | Length (was 12 s) | What it shows |
|---|---|---|---|---|
| Tempo only: speed 75 % | 439.99 Hz | ×0.750 (90 BPM) | 16.000 s | Slower, same pitch |
| Pitch only: +2 semitones 30 cents, speed 100 % | 502.51 Hz | ×1.000 | 12.000 s | Higher, same tempo |
| Both apart: +5 semitones, speed 150 % | 587.32 Hz | ×1.500 | 8.000 s | Each moves by its own amount |
| Linked (record): +4 semitones | 554.36 Hz | ×1.260 | 9.524 s | Pitch and tempo rise together |
| Linked (record): −12 semitones | 220.00 Hz | ×0.500 | 24.000 s | One octave down = half speed |
The linked rows follow the formula in Table 2 exactly: +4 semitones = ×1.2599 speed. The other rows prove the opposite: with time-stretching, 75 % speed moved the tone by less than 0.03 cents. The test method is linked at the end of this page.
Which should you change: pitch or tempo?
- Change the pitch when the song is too high for your voice or too low. Pitch problems are range problems: 1–3 semitones usually fixes them; the key for your vocal range shows how to pick the number.
- Change the tempo when a passage is too fast to learn. Practise at 75–90 %, then go back up in 5 % steps. Tempo problems are practice problems, not voice problems.
- Change both for a practice track: a song at 128 BPM that sits 2 semitones too high becomes −2 semitones at 85 % (108.8 BPM).
- Change them together only for the effect: nightcore-style speed-ups and slowed-down edits are linked changes.
How to change pitch and tempo separately (4 steps)
- Open the file in the Pitch and Tempo Changer (MP3, WAV, M4A and more; nothing is uploaded).
- Set the pitch in semitones: −2 lowers the key by a whole step.
- Set the tempo as a speed % or type a target BPM; leave the link switch off to keep them independent.
- Preview and download the WAV or MP3; the file name shows both changes.
Other routes: Audacity has separate effects for pitch, tempo and speed; the video pitch changer changes a video’s sound and speed; the YouTube pitch changer works while a video plays.
Pitch vs key vs tempo
Pitch is the height of one note; the key is the set of notes a song is built around (what a song key is); tempo is the speed. A pitch change of whole semitones changes the key; a tempo change never does. The full comparison of the first two is in key change vs pitch change, and the definition of pitch in what pitch is in music.
Frequently asked questions
Does changing the tempo change the pitch?
Not with a time-stretching tool: in our test, 75 % speed moved a 440 Hz tone by less than 0.03 cents. Playing audio faster like a tape does raise it: +12.25 % speed = +2 semitones.
Does changing the pitch make a song faster?
No. A pitch shifter keeps the length and BPM. Only a linked “speed” change (tape, record, varispeed) makes a higher song faster as well.
Why does pitch change with speed?
Playing a recording faster makes every wave cycle arrive sooner, so every frequency rises by the speed ratio. Semitones = 12 × log2(speed): double speed = +12 semitones, one octave.
What is the difference between speed and tempo?
Tempo is the musical speed in BPM. Playback speed is a percentage of the original recording; 80 % speed turns 120 BPM into 96 BPM. In apps, “speed” often changes the pitch too.
What should a musician adjust to change the speed of a song without altering the notes?
The tempo, with a time-stretching tool. The notes (pitches) and the key stay the same; only the BPM and the length change.
Is pitch the same as key?
No. Pitch is one frequency; a key is a set of notes around a home note. Moving every pitch by whole semitones changes the key.
More free pitch, key and tempo tools are on the Online Pitch Changer home page, including the karaoke pitch changer for backing tracks.