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Free BPM Finder and Key Finder Online

Find the BPM and musical key of a track with a free BPM finder that works in your browser. Drop in an audio file and read the estimated tempo, key and confidence.

Where to go next

BPM Finder features

Three readings in one pass, all calculated on your device.

  • A wooden metronome with a brass weight on its pendulum and a blank face, beside a coral flower

    Tempo in BPM

    Measures onsets and repeating peaks to estimate the tempo; check half-time and double-time readings by ear.

  • Twelve blank white discs in a circle on a wooden desk, with a coral flower and a gold ribbon

    Key and scale mode

    The key finder sums spectral energy into twelve pitch classes and compares them with major and minor profiles.

  • A clear glass pane and a frosted glass pane standing on a wooden desk, with a coral flower

    Confidence readout

    An uncalibrated confidence score from the BPM finder shows whether the pattern was clear or ambiguous.

  • A stack of plain kraft sleeves, coral headphones, blank cards and a teal ribbon on a wooden desk

    Sample library prep

    Check the tempo and key of loops and samples before you tag, sort or import them.

Who uses BPM Finder

  • A beatmaker sampler with unlabeled pads, an analog tuner meter and a blank-label vinyl 45

    Producers and beatmakers

    Confirm the tempo and key of a sample with the BPM finder before importing it.

  • A vinyl record on a cream felt slipmat beside olive DJ headphones and a tap-tempo box

    DJs and crate-diggers

    Use the BPM finder and key finder to plan harmonic mixes and sort tracks into playlists.

  • A wooden metronome and a pair of tap-dance shoes

    Students and teachers

    Compare the estimate with what you hear when you practice rhythm and tonality.

  • An analog clock with no numerals, a small tuner knob box and a blank cue sheet

    Composers and sound designers

    The BPM finder spot-checks a cue, loop or ambient texture without opening a project.

Why choose BPM Finder

  • Runs on your device

    BPM Finder works in your browser, so your files stay on your device unless you save a result.

  • Tempo, key and confidence

    One pass with the BPM finder gives you an estimated BPM, root key, scale and an uncalibrated confidence reading.

  • Straight about estimates

    Half-time and double-time readings are flagged, and the results are labelled as estimates to check by ear.

  • Free to use

    BPM Finder is free and uses no credits. You only need an account to save results.

More tools to use with the BPM Finder

Browser tools on SampLab Pro run on your device; the AI tools need an account.

AI creation

Edit audio

Analysis tools

How to use the BPM finder

  1. A hand setting down a plain kraft sleeve beside a wooden metronome and coral headphones
    1

    Drop in an audio file

    Drag a file or loop into the BPM finder, or pick one from your device. Files can be up to 50 MB and 10 minutes long.

  2. A wooden metronome with its pendulum tilted, beside coral headphones on a wooden desk
    2

    Wait for the analysis

    The BPM finder decodes the audio and measures onset timing and pitch-class energy on your CPU, so nothing is uploaded.

  3. A wooden metronome, a circle of blank white discs and a glass marble on a wooden desk
    3

    Read tempo, key and confidence

    Use the estimated BPM and key as a starting point for time-stretching or transposing, and check them by ear.

A BPM finder in your browser

This BPM finder estimates the tempo, root key, scale mode and confidence of an audio file without uploading it.

Checking the tempo and key of a sample should not mean opening a DAW. The BPM finder and key finder analyse the decoded audio on your device: onset gaps give the tempo, and the spread of energy across twelve pitch classes gives the key.

Both values are estimates. Confirm them by ear before you build an arrangement around them.

A wooden metronome with a blank face, coral headphones and a teal ribbon on a sunlit desk

BPM finder or full production software

When a quick estimate is enough, and when you need a DAW.

NeedGood fitLimitsUse full software when
Quick tempo and keyShows estimated BPM, key and confidence.Half-time or double-time readings can appear.You need verified transcription.
Private analysis without uploadingAudio never leaves your device.Decoding depends on your browser formats.You work with session files.
Tracks whose tempo or key changesGives one dominant tempo and key per clip.Rubato, drift and key changes are not detected.You need beat mapping or tempo automation.

All estimates are automated, so check them by ear.

How the BPM finder and key finder work

To estimate tempo, the BPM finder builds an onset curve that tracks sudden rises in spectral energy, then looks for the most prominent repeating interval. Syncopated, swung or polyrhythmic music can have several valid readings.

For the key, the spectrum is folded into twelve semitone bins and compared with major and minor templates. Dense chords, percussion and heavy reverb can hide the tonal centre, so treat the key and the confidence score as guides.

A wooden metronome with a blank face, coral headphones and a teal ribbon on a sunlit desk

Get a reliable reading from the BPM finder

The BPM finder and key finder use your browser's audio decoder and run locally. Confidence is a guide, not a certainty, and tempo detection can land on half-time or double-time values, so confirm the figures by ear.

Ready to try BPM Finder?

Drop a track into the tool above to read its tempo and key. The BPM finder and key finder are free, and your audio stays on your device.

Open BPM Finder

BPM Finder FAQ

Is this BPM finder free?

Yes. The BPM finder is free, uses no credits and needs no account or installation.

How accurate is the BPM finder?

The BPM finder gives a useful estimate, not a guarantee. Dense polyphony, live drumming and heavy reverb can skew the result, so check by ear.

What does the key finder tell me?

The key finder estimates the root note and whether the track sounds major or minor, from how energy spreads across the twelve pitch classes. Treat it as a guide and confirm by ear.

Which audio formats does the BPM finder support?

WAV, MP3, FLAC and OGG files up to 50 MB and between 1 second and 10 minutes long, as long as your browser can decode them.

Is my audio uploaded when I use the BPM finder?

No. The BPM finder runs in your browser tab, and the audio is discarded from memory when you close or reload the page.