Key Detector – Musical Key & BPM Finder

Find the key, BPM and chords of a song. Change key and speed on YouTube for free, loop any part and practice. Audio stays local.

🎵 KEY DETECTOR — KEY, BPM AND CHORDS, THEN PRACTICE YOUR WAY Find the key, tempo and chords of the music playing in Chrome, then change its key and speed to practice it your way. Audio is analyzed on your device. ✨ NEW IN 2.0 • Changing the key and speed on YouTube is now free, along with the A–B loop. • Chords over the video and a printable chord chart, free on 3 songs a month. • A new engine for key, tempo and chords. • Opens in Chrome's side panel by default, with dark mode for everyone. • A Player for songs on your computer, with separate vocals, drums and bass (Pro). • A song library with setlists, versions per singer and links to share (Pro). • Pro is now monthly, yearly or a one-time lifetime purchase, with a 7-day free trial. 🔍 FIND THE KEY, TEMPO AND CHORDS • Detect the key and BPM of the song playing in the tab from a 15- or 30-second sample (45 and 60 seconds with Pro). • Live mode updates the estimate as the music changes. • Pick a music style (General, Worship, Electronic or Fast electronic) to suit what you play. • See alternative keys, the tuning of the recording and the chord progression. • Analyze audio files from your computer, such as MP3 or WAV, without playing them: one every 7 days for free, unlimited with Pro. Results are estimates. The percentage shows how closely the audio matches a key; it is not the probability of being right. Trust your ear. 🎛️ CHANGE KEY AND SPEED ON YOUTUBE — FREE • Transpose ±12 semitones without changing the speed (±24 with Pro). • Slow down or speed up from 0.25× to 2× without changing the pitch (up to 4× with Pro). • Fine-tune by ±50 cents, or match the recording to A440 in one click. • Loop any passage with A–B and control playback from the side panel. • Change the key of music playing on other websites too. 🎸 CHORDS OVER THE VIDEO AND A PRINTABLE CHART (BETA) • The current chord appears over the YouTube video as it plays. • Get the chords for the whole song in about a quarter of its length. • Open a chord chart with guitar, ukulele, mandolin or piano diagrams, a suggested capo and Nashville numbers. • Correct any bar, transpose the chart, print it, copy it as text or export it as MIDI. • Free on 3 songs a month, unlimited with Pro. Chords are detected automatically and are not 100% accurate. ⭐ PRO • Player: open a song from your computer with its waveform, synced chords and diagrams, loops, key and speed. • Separate tracks: mute the vocals, drums or bass, or keep only the vocals. It runs on your computer. • Sound: equalizer presets, vocal reducer, natural voice when transposing and a tape effect. • 4- and 8-bar loops, named markers, clips and sequences, and a practice ramp that speeds up a little on each loop. • Song library: save each song with its key, speed, loop, chart and notes. Versions per singer, printable setlists, links to share and backups. • MIDI pedal and controller support, unlimited history, Camelot notation and five color themes. 🎹 FREE PRACTICE TOOLS • Interactive piano with scales, tap tempo and a metronome with count-in. • Instrument tuner with your microphone, only when you start it. • Song bar and playback controls in the side panel. • Note names as C-D-E or Do-Re-Mi, in English, Spanish or Portuguese. 💳 FREE AND PRO Free: key and BPM detection, Live mode, key and speed changes on YouTube, the A–B loop, chords and charts on 3 songs a month, the side panel, dark mode, piano, metronome and tuner. Pro: chords and file analysis without limits, the Player with separate tracks, sound tools, the song library, longer analyses and more. Try it free for 7 days, with no card and no automatic charge. Then choose monthly, yearly or a one-time lifetime purchase. 🔒 PRIVACY Audio is analyzed on your device and is never uploaded. Your songs and settings are stored locally in Chrome. The extension sends anonymous usage counts to improve the product; they never include audio, video titles, page addresses, file names, detected keys or your email, and you can turn them off in Settings. If you start the trial or buy Pro, ExtensionPay and Stripe process your email to manage your license. Privacy policy: https://keydetector.site/privacy ℹ️ COMPATIBILITY Key detection works on pages where Chrome allows tab audio capture; protected media and Chrome's own pages cannot be captured. Studio is designed for YouTube; key changes on other sites work while the side panel stays open. Requires Chrome 116 or later. User guide: https://keydetector.site/guide/ If Key Detector helps your practice, a review helps other musicians find it.