Key & Harmony

Find the BPM of a Song

Drop in a song and get its BPM in seconds, with its musical key alongside it. You get precise decimal BPM plus half and double-time alternates, the key as a name, a Camelot code and Open Key notation, and an energy rating. Detection runs entirely in your browser, so your files never leave your device. AIFF works too, even though browsers can't normally decode it, and you can export everything as CSV for free.

On-device analysis
Audio never uploads
Results stay local

Method

How It Works

Drop an audio file (or several) into the analyzer above
Your browser decodes it and resamples to the analysis rate, all locally
Tempo detection scores thousands of beat-grid candidates against the onset pattern of the track
Key detection runs a neural network over the full harmonic spectrum, the same model that ships in the Vibes app

Analyzing a File vs Looking Up a Released Song

This analyzer is for audio files you have on your device: promos, downloads, your own productions, untagged edits. If you want the key and BPM of a released track you don't have as a file, you can search our track database instead; it covers tens of thousands of electronic releases with key, BPM, energy, and harmonic-mixing suggestions per track, or browse by key via the artist directory.

Reading a File, Tapping It, or Looking It Up

There are only three ways to get a tempo, and they suit different moments. Reading the file is the most exact: a beats per minute finder measures the audio itself, so it works on promos, edits and your own bounces, and it is the only method that also gives you the key. Tapping is the fastest when there is no file at all, which is what the tap tempo tool is for: a track on the radio, in a club, or a live band. Looking the number up in a database is quickest for a released track you do not own, and our track database covers tens of thousands of releases. A music tempo finder that reads the file, like this one, is the one to reach for when the answer has to be right rather than close.

Your Files Never Leave Your Device

Most online key and BPM finders upload your audio to a server for processing, which means waiting on the upload, size limits, and your unreleased edits sitting on someone else's machine. This tool works differently: the analysis engine is compiled to run inside your browser. Decoding, tempo detection, and the key-detection neural network all execute on your own device. Nothing is transmitted, stored, or queued. That matters if you are analyzing unreleased promos, your own productions, or bootleg edits you would rather not upload anywhere.

Reading the Result

BPM is the snapped whole-number tempo DJs use; the precise decimal underneath is what your DJ software will show after beat-gridding
Half / double time shows the same groove counted at half or twice the tempo. Genres like drum & bass and dubstep are routinely written one way and felt the other, so if the main reading feels wrong, one of these is your answer
Key is shown three ways: musical name (A minor), Camelot code (8A), and Open Key (1m). Click the Camelot code to browse tracks in the same key in our track directory
Energy is a 1-10 intensity rating in the Mixed In Key tradition, estimated from loudness, dynamics, bass weight, percussive activity, and tempo of the beat-active section. Use it to sort warm-up material from peak-time weapons
Confidence tells you how unambiguous the detection was. Low BPM confidence usually means sparse or shifting percussion; low key confidence usually means heavy atonal content or long mixed sections

What to Do With Key and BPM

Once you know a track's key and tempo, harmonic mixing is mechanical: tracks mix cleanly with others that share their Camelot code or sit one step away on the wheel. Use the key compatibility checker to test a specific pairing, the harmonic mixing chart as a full reference, or the key transposer when you plan to pitch a track up or down. For tempo planning across a whole set, the halftime/doubletime calculator and set time calculator pick up where the analyzer leaves off.

Batch Analysis and CSV Export

Drop as many files as you like; they queue up and analyze one after another, and your results stay saved on this device between visits. The Export CSV button downloads everything (BPM, precise BPM, half/double-time, key in all three notations, energy, confidence) as a spreadsheet-ready file, free and without an account. AIFF users get special treatment: browsers can't decode AIFF natively, so this tool ships its own AIFF reader, covering the format most DJ libraries actually run on.

Analyzing One Track vs Your Whole Library

This page is built for spot checks: a promo you just downloaded, a track someone sent you, a file with missing tags. If you need key and BPM across thousands of files, plus playlists organized by energy and mood, that is what the Vibes app does. It runs this same analysis engine across your entire library automatically and writes the results where Rekordbox, Serato, and Traktor can read them.

Hey, it's Ben Modigell 👋

I've been DJing and producing music as "so I so," focusing on downtempo, minimal, dub house, tech house, and techno. My background in digital marketing, web development, and UX design over the past 6 years helps me create DJ tutorials that are clear, practical, and easy to follow.

DJingMusic ProductionTech HouseMinimal HouseDigital MarketingWeb DevelopmentUX Design

Methodology

Last updated August 19, 2026

Author and Methodology

Maintained by Ben Modigell, founder of Vibes. Ben builds DJ library, preparation, BPM, and harmonic-mixing tools for working DJs.

Data used: Benchmarked against 952 professionally keyed and beat-gridded reference tracks (Mixed In Key ground truth). The in-browser BPM engine is a verified port of the Vibes desktop engine (identical output on all 318 benchmark samples when analyzing the same audio), and its rhythm-aware analysis-window selection scores 85% within ±2 BPM on the 318-track benchmark, ahead of fixed-window analysis at 83%.
Source: Vibes analysis engine (in-browser build)
Evidence: Page output checked against the current tool behavior and internal DJ reference data.
How this page is made: BPM detection is a direct port of the Vibes desktop analyzer (onset-envelope autocorrelation with beat-grid alignment scoring). Key detection runs the S-KEY neural network (ICASSP 2025) via WebAssembly, using the same model weights as the desktop app. All analysis happens on your device.

BPM, key, and genre labels can vary by edit, remaster, detection engine, and DJ software. Use these pages as a practical mixing reference, then verify important tracks in your own library.

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Frequently Asked Questions

Drop the audio file into the analyzer above and it detects the musical key automatically, shown as the key name (like A minor), its Camelot code (8A), and Open Key notation (1m). Detection runs a neural network trained on musical key recognition, the same model the Vibes desktop app uses.

No. The entire analysis runs inside your browser using WebAssembly. Your file is decoded and processed on your own device and never leaves it. That is also why the tool is fast and free with no file-size pricing: there is no server doing the work.

The detector is benchmarked against a library of over 950 professionally keyed and beat-gridded reference tracks (Mixed In Key ground truth). Most misses are half-time or double-time readings rather than wrong tempos, which is why the result always shows half and double-time alternates. A 174 BPM drum and bass track heard as 87 BPM is the same groove; the alternates row lets you pick the reading that matches how you'd count it.

MP3, WAV, FLAC, M4A/AAC, OGG, Opus, and AIFF. AIFF deserves a special mention: most browsers cannot decode it natively, so this tool ships its own AIFF reader. Tempo is measured from the most rhythmically active 30 seconds of the track (so a long beatless intro doesn't skew the result), and key detection listens to up to the first five minutes.

Upload the file above and the tempo is detected in seconds, shown as the DJ-standard whole number plus the precise decimal BPM your software would show after beat-gridding. If a track feels twice as fast or slow as the number suggests, check the half/double-time alternates: genres like drum and bass are written at 174 BPM but often felt at 87.

Yes. Drop an instrumental, beat, or loop (MP3, WAV, or any supported format) and you get its key and BPM the same way. That covers the classic producer workflow: finding the key of a beat before writing a topline, checking which acapellas fit, or matching samples harmonically before flipping them.

Upload the instrumental or full song here, read the detected key (for example A minor), and set your pitch-correction plugin (Auto-Tune, Melodyne, MetaTune) to that key and scale. If the detected key is a relative pair away from what your plugin expects (A minor vs C major), both share the same notes, so either setting corrects to the same pitches.

Both systems arrange the 24 musical keys on a clock face so compatible keys sit next to each other. Camelot (used by Mixed In Key and rekordbox) labels them 1A-12A for minor and 1B-12B for major. Open Key (used by Traktor) labels the same positions 1m-12m and 1d-12d. C major is 8B in Camelot and 1d in Open Key. This tool shows all three notations for every result.

One pass gives you both, so this is a key and bpm finder rather than two separate pages. That matters for prep: tempo alone tells you what beatmatches, key alone tells you what blends, and only the pair tells you whether a transition will actually work.

This is one: drop the file on the mp3 bpm finder above and the tempo comes back in seconds, no account and no per-file charge. Being a BPM detector free of cost is normally the trade-off for an upload queue, but here the analysis runs on your own machine, so there is nothing to meter and nothing to pay for.

Nothing meaningful: BPM finder, bpm checker, bpm analyzer and tempo detector are all names for measuring tempo from audio. The real split is how the measurement is taken. A song bpm finder reads a file, as this page does. A bpm counter online usually means tapping along by hand, which is what the tap tempo tool is for. A lookup service reads a number someone else already published for a released track.

Most do. Almost every online bpm analyzer sends your audio to a server, which is why they queue and cap file sizes, and a bpm analyzer online is only as fast as your upload. This one does not: the same engine runs as WebAssembly in the page, so using it as an online bpm detector costs you no upload time and leaves unreleased material on your own disk. If you would rather compare installed options, we keep a roundup of bpm analyzer software separately.

Yes, both run on the same pass. As a key detector it returns the musical name, the Camelot code and Open Key notation; as a tempo checker it returns the whole number, the decimal, and the half and double-time alternates. That is why the page is a key and bpm detector rather than two separate tools, and why a key finder mp3 workflow and a tempo one are the same drop here.

Yes. Drop as many files as you like and they queue locally, one after another, with results kept on the device between visits. A song tempo finder online that runs server-side would charge or throttle at this point; here the only limit is how fast your machine works.

BPM tells you which tracks can be beatmatched without large tempo changes, and key tells you which tracks blend harmonically without clashing. Mixing within compatible keys (same Camelot number, or one step away) keeps basslines and melodies consonant through a transition. Together they are the two numbers that define whether two tracks can be mixed cleanly.

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