The song is decoded and analysed by your own browser. Nothing is uploaded. Find the tempo in beats per minute and the musical key of a song, or tap along to count the beat yourself. It is free and private.
How to find a song's tempo and key
- Open the From a song file tab and press Choose a song. MP3, WAV, M4A, AAC, OGG, Opus, FLAC, WebM and MP4 files can be used.
- Wait while the song is analysed.
- Read the BPM, the key and the confidence shown with each.
- Press Choose another for a new song, or Reset to clear the result.
No file handy? Open the Tap tempo tab and tap along to the music instead.
How the tempo is found
The tool listens for the moments where the sound suddenly gets louder or brighter, such as drum hits and plucked notes, and builds a pulse curve from them. It then looks for the time gap that repeats most strongly through the song and turns it into beats per minute between 60 and 200. Many songs can be counted at half or double speed, so both are shown; pick the one that matches how you would clap along.
How the key is found
The sound is split into its frequencies and folded into the twelve notes of the scale, so the tool knows how much of each note the song contains. That note profile is compared with the well-known Krumhansl-Schmuckler profiles for every major and minor key, and the closest match wins. The relative key shares the same notes, and the Camelot code helps DJs find songs that mix smoothly: neighbouring numbers, or the same number with A and B swapped, usually blend well.
How accurate is it?
These are estimates. They work best on music with a steady beat and a clear tonal centre, such as pop, dance, rock and hip-hop. Songs that change tempo or key, live recordings that drift, and ambient or very percussive tracks are harder, and the confidence word drops to tell you so. If a result looks off, try the tap tab and trust your ears.
Tap tempo
Tap the button, the space bar or the T key in time with the music. The tempo is the average of your most recent taps, so it settles after a few beats. Stop for two seconds and the next tap starts a fresh count.
Common uses
- Musicians choosing the tempo for a metronome or backing track.
- DJs and event hosts building a playlist that flows from one song to the next.
- Fitness instructors and runners matching songs to a pace.
- Video editors cutting footage to the beat.
- Singers checking which key a song is in before picking a range.
To check your instrument's pitch, try the guitar tuner. To speed up or slow down a track, use the audio editor.
Questions
Why does it show two tempos?
Many songs can be counted at half or double speed. Pick the one that matches how you would naturally clap along.
What is a Camelot code?
It is a number and letter that labels each key so DJs can see which songs mix well together. Neighbouring numbers, or the same number with A and B swapped, usually work.
Is my song uploaded?
No. It is analysed in your browser and stays on your device.