TempoKey: BPM Analyzer

Know every song's tempo before you walk on stage.

TempoKey analyzes an audio file you already own and returns its BPM in seconds — and it always shows two readings, the primary tempo and its half-time or double-time alternative, because that ambiguity is real in almost every library. You choose the one that matches how you count the song. From there it goes straight into a setlist you can reorder, annotate, and read from the stage.

WHAT'S INSIDE

• Automatic BPM analysis — Import a local audio file through the Files picker or drag and drop, and an on-device engine returns the tempo: Apple's Music Understanding framework on iOS 27, or the built-in DSP engine on earlier systems. Nothing is uploaded, nothing is copied, nothing leaves your phone.

• Dual reading, by design — Every result shows a primary BPM next to its half-time or double-time alternative, for example "87 · or 174". One tap swaps them, and you can type a value in by hand when you disagree with both.

• Song Map and auto key on iOS 27 — See the song's structure at a glance: sections, bar grid, where vocals, drums and bass enter, and overall loudness. The detected key is shown with an honest alternate reading; a key you type yourself always takes priority. On earlier systems the key field is typed in by you.

• Tap tempo — Tap along four or more times and watch the tempo settle live. Made for rehearsal rooms, live counts, and anything you cannot import as a file.

• Setlist library — Build ordered setlists with song title, BPM, a musical key, and your own notes. Drag to reorder until the running order is right.

• Home screen widgets — An extra-large widget shows the next song in your setlist with tempo and key, readable from across the stage (iOS 27; medium size on earlier systems).

• Performance Mode — A large-type card built for a dark stage: title, tempo and key readable at a glance, swipe left and right to move through the set, screen stays awake.

• Transpose and tempo math — Capo and semitone transposition, BPM to milliseconds for delay and echo, and 75% / 50% practice-speed references. Pure arithmetic, no audio processing.

• Spotlight and Siri — Your songs and setlists are searchable from the system search and openable by Siri (iOS 18.4 or later).

• Completely offline — No account, no sign-in, no network requests, no cloud sync, no ads.

WHAT TEMPOKEY IS NOT

• Not a metronome. The app makes no sound at all. • Not a player. There is no playback, no now-playing screen, no media library browsing. • Not a tuner, not a notation app, not an audio editor. • No subscription, no advertising, no account.

FILE SUPPORT

Local, DRM-free audio only — MP3, WAV, M4A, AIFF and FLAC, imported from Files or dropped in. DRM-protected downloads cannot be analyzed, and the app says so plainly instead of failing quietly. Tempo detection covers 50–210 BPM; outside that range you get an explicit message rather than a wrong number.

PRIVACY

Your audio is decoded in memory for the length of the analysis and then released. TempoKey never copies, caches or uploads a file. Only the results — tempo, alternative reading, confidence, file name and duration — along with your setlists and notes are stored on the device. The app requests no microphone, no media library, no location, no contacts and no photos.

PAY ONCE

TempoKey opens and works without a purchase: tap tempo and every calculator are always free, and so are your first three analyses and one setlist of up to five songs. A single Lifetime unlock removes the limits — unlimited analyses, unlimited setlists and songs, and Performance Mode. One payment, no subscription.

Built for the ten minutes before you go on.