Free · In your browser · Nothing uploaded
BPM changer: any sample, at your project's tempo.
Drop a song or a loop in. The tempo and key are detected, you type the BPM you need, and it is re-timed with the pitch left where it was. Download it, or put it straight on a TAIL pad and play it against your beat.
How it works
How to change the BPM of a song
Drop the audio in
A song, a loop, a sample. The tempo and key are detected on the spot — about half a minute for a four-minute song.
Type the new BPM
The detected tempo is filled in. If it read half or double time, fix it with ½× or 2×, then type the BPM you want.
Render and play
Change BPM renders the file. Download it, chop it, or load it onto a TAIL pad.
What producers use it for
Why producers change the BPM
Fit a sample to your beat
The loop is 92, your project is 88. Type 88, and the sample sits on the grid without the pitch drifting with it.
Line up an acapella
Extract the vocal, bring it to your tempo here, then move it to your key with the key changer. Remix prep in three steps.
Practice at a slower tempo
Take a fast part down ten or twenty BPM and learn it at a speed you can play, in the original key.
DJ and mashup prep
Two tracks, one tempo. Change one to match the other before they ever reach the decks.
Tempo without pitch
The BPM changes, the key does not
This is a time-stretch: the audio gets faster or slower and keeps its pitch, so a sample in A minor is still in A minor at the new tempo. That is the opposite of the speed changer, where pitch follows speed on purpose, like a record — the sound of sped-up and slowed edits.
You can change the key at the same time: the key controls are under the tempo, and the key changer is the same tool with the key first. The range is a quarter of the original speed up to double; the ½× and 2× buttons handle the cases where a track is felt in half time.
How the tempo is found
Detected, then yours to correct
The tempo comes from Beat This!, an open beat-tracking model from JKU Linz (MIT licence); the key from S-KEY, Deezer's open key model (MIT). Both run in your browser after a one-time download of about 12 MB.
Tested with the same models and pipeline on the GTZAN dataset, the tempo was within 4% for about eight in ten excerpts, and most misses were exactly half or double — which is why the original BPM field stays editable. If you already know the tempo, just type it.
More TAIL tools
Everything else that runs in the same tab
Key changer
Transpose a song or sample into another key without changing its tempo.
Acapella extractor
Pull the vocal out of a song, then bring it to your tempo here.
Sample chopper
Chop the re-timed loop into slices and play them on 16 pads.
Common questions about changing the BPM
Drop the song on this page. The current tempo is detected and filled in; type the BPM you want in New BPM and press Change BPM. The result plays right on the page and downloads as an MP3.
No. The audio is time-stretched, so the pitch and key stay the same. If you want pitch to follow speed, like a record, use the speed changer instead.
Press ½× or 2× next to the original BPM, or type the tempo you hear. Half and double time are the most common detection misses, and the change is calculated from whatever is in that field.
Free, no signup, no watermark. Nothing is uploaded: the detection models download to your browser once and the audio is processed on your device.
From a quarter of the original speed to double. Small changes — a few BPM either way — sound the most natural; the further you stretch, the more audible the processing gets.
The tempo and key detection reads up to ten minutes per file. A longer file is offered a split into parts.