How to Find the BPM and Key of a Song
Before you set a metronome, pick a capo position or build a setlist, you need two numbers: how fast the song is and what key it's in. Here's how to find the BPM of a song and its key automatically on iPhone, and how to check both by ear so you're never stuck trusting a number that feels wrong.
Import the song into Song Practice. It detects the key and tempo and shows them under the title, for example C♯ MAJ · 97.3 BPM. To double-check the tempo, count beats for 15 seconds and multiply by 4. To check the key, hum the note the song wants to end on.
Why you need the BPM and key
The tempo tells you where to set your metronome, how far you'll need to slow the song down to practice it, and whether two songs will flow together in a set. The key tells you which scale to solo in, which chords are likely to show up, and how many semitones to shift if the song sits badly for your voice or tuning.
Step by step: a BPM and key finder on iPhone
- Get Song Practice. Download it free from the App Store for iPhone or iPad.
- Import the song. Pick it from Files, your iTunes library, Photos, cloud storage, or paste a link.
- Read the result. Key and tempo appear under the song title, for example C♯ MAJ · 97.3 BPM. That's your answer for most songs.
- Turn on the metronome. It locks to the song's detected tempo. If the click sits right on the kick and snare, the BPM is right.
- Open the song analysis. On iOS 27, See inside the song lays the track out on a timeline with beats and bar numbers, sections, phrases and the key.
What the song analysis shows you
The analysis runs on your device and goes well beyond one BPM figure. On the timeline you can see:
- Beats and bar numbers, so you can say "the fill in bar 33" instead of "about two minutes in".
- Sections, segments and phrases, which show the song's form at a glance.
- The key, alongside everything else.
- Where each instrument plays: vocals, drums, bass and other. Handy for spotting the bar where the bass drops out.
- Loudness (LUFS) and pace, which show where the song builds and eases off.
Bar numbers and sections make the next step much easier: set an A-B loop on exactly the bars you want to learn.
How to check the BPM by ear
Detection is fast, but it's good practice to confirm the number yourself, especially on live recordings or songs with a loose feel.
- Find the pulse. Tap your foot to the song. Most pop and rock songs have a snare on beats 2 and 4, so tap once for every kick and snare.
- Count for 15 seconds. Start counting on a strong beat, from zero, and stop at 15 seconds.
- Multiply by 4. 24 taps in 15 seconds is 96 BPM. Your count will be within a few BPM of the real tempo, which is close enough to confirm the detected number.
Half-time and double-time: the most common mix-up
If your count comes out at roughly half or double the detected BPM, neither of you is wrong. A song at 140 BPM with a heavy backbeat can feel like 70, and a slow ballad at 60 can be counted as 120 if you follow the hi-hat. Both numbers describe the same song.
Pick the one that matches how musicians would count the song in. A useful rule: if the snare lands on every other tap, you're counting the right pulse for most pop and rock. If the snare lands on every tap, you're probably counting in double-time.
| You count | Detected | What it means |
|---|---|---|
| About the same | 96 BPM | Confirmed. Set your metronome and go. |
| About half | 140 BPM | You're feeling half-time. Common in hip-hop, metal breakdowns and trap. |
| About double | 65 BPM | You're following eighth notes, often the hi-hat. Count the snare instead. |
| Drifting all over | Any | Live or unquantized recording. The tempo genuinely moves; use the beat grid on the timeline. |
What key is this song in? Check it by ear
A key has two parts: the tonic, the home note, and the quality, major or minor.
- Find the tonic. Listen to the end of the chorus or the final chord of the song and hum the note that feels like home, the one that sounds finished. Then find that note on your instrument.
- Decide major or minor. Play a major chord and a minor chord on that note while the song plays. The one that blends is the key. Major usually sounds bright and settled; minor sounds darker.
- Compare with the detected key. If they match, you're done.
Relative major and minor confusion
Every major key shares all its notes with a minor key three semitones below it. C major and A minor use the same seven notes, as do G major and E minor. So a detector, or your own ear, can land on the relative key instead. If Song Practice says A minor and you hear C major, ask which chord the song rests on at the end of each section. That chord's root is the tonic. Both keys use the same scale, so for soloing either answer gives you the right notes.
You'll also see enharmonic names: C♯ major and D♭ major are the same pitches written two ways. If the title reads C♯ MAJ and a chord chart says D♭, they agree.
Use the BPM and key in your practice
With both numbers you can set up a practice session in a minute. Loop the hard section, slow it to 80% (the metronome follows), and work up in 5% steps. Knowing the key also gives you a head start when learning a song by ear: you already know which notes are likely before you play one.
Common questions
Why does the BPM show a decimal, like 97.3?
Many recordings, especially older or live ones, don't sit exactly on a whole number. The decimal is simply a more precise reading of the tempo. Round it for a setlist; for practice, the more exact figure is the one to trust.
Can a song change key or tempo partway through?
Yes. Key changes before a last chorus are common, and live bands speed up. If the detected number feels wrong for one part of the song, loop that section and check it by ear with the methods above.
Do I need iOS 27 to see the BPM and key?
No. Key and BPM detection works on iOS 17 and later. The full song analysis timeline requires iOS 27.
Find the tempo and key in seconds
Free on the App Store. Detected automatically when you import a song.
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