Are metronome apps accurate?
A good metronome app can keep time to a small fraction of a millisecond, but only if it places each click on the audio clock. We recorded ours on a Galaxy S23 for 30 minutes with the screen off: 3,015 clicks, none missed, and the gap between clicks never changed by more than 0.02 ms. Apps that use an ordinary timer can wobble by many milliseconds, and any app can stop when the phone goes to sleep.
By Springlab · 20 October 2026. We make Metronome & Tuner. Many metronome apps say they have "zero drift", but we could not find anyone who had measured one. So we measured ours. This page shows the numbers, how we got them, and what we have not tested yet.
What "accurate" means for a metronome
There are four separate questions. An app can pass one and fail another.
| Question | What it means | At 100 BPM |
|---|---|---|
| Tempo | Is the speed right? | One click every 600 ms |
| Evenness | Is each gap the same as the one before? | Every gap 600 ms, not 598 then 603 |
| Drift | Does it slowly speed up or slow down over minutes? | Click 1,000 still lands on the beat |
| Missed clicks | Does a click ever go silent? | None, even with the screen off |
Evenness and missed clicks matter most while you play. Our own pass mark for the app is 2 ms: 95 % of gaps within 2 ms of each other, and no missed click. A missed click is the worst failure, because it throws you off the beat.
What we measured
We ran the Metronome & Tuner app at 100 BPM on a Samsung Galaxy S23 three times:
| Test (100 BPM) | Clicks | Missed | Even to | Drift / min |
|---|---|---|---|---|
| Screen on, 2 min | 205 | 0 | 0.02 ms | 0.06 ms |
| Screen off, 30 min | 3,004 | 0 | 0.02 ms | 0.002 ms |
| Screen off, deep sleep, 30 min | 3,015 | 0 | 0.02 ms | 0.001 ms |
"Even to" means 95 % of the gaps between clicks were within that much of each other. 0.02 ms is one audio sample at 48,000 samples a second. That is the smallest step our recording can see, so the real wobble may be smaller still. A drift of 0.001 ms per minute means about 17 hours of nonstop playing before the beat is one millisecond off.
Deep sleep (Android calls it Doze) is what a phone does when it lies still with the screen off. It is when many apps are stopped to save battery. We forced it on for the third test, because a phone on a charging cable never sleeps.
How we tested
- A small test app on the same phone recorded the phone's own sound output at 48,000 samples a second, with the phone's clock time for each block of sound.
- We started the metronome with a foot pedal key, so no finger touched the screen, and then locked the screen.
- A script found every click in the recording and compared it with a perfect 100 BPM grid.
What we have not tested yet: other phones, other tempos, and Bluetooth speakers or headphones. Bluetooth adds a delay of its own. That makes every click late by the same amount, so it moves the whole beat but does not make it uneven.
Why some apps drift or skip
- A timer instead of the audio clock. An app that says "play a click, wait 600 ms, play a click" depends on how busy the phone is. Each wait can run a little long, and the errors add up. An app that writes each click into the sound stream at an exact sample cannot drift that way.
- The screen goes off. To save battery, Android stops apps that are not built to run in the background. The click stops, or comes back late. A metronome needs to run as a proper background service, like a music player.
- A browser tab. A web metronome, ours included, can plan its clicks on the audio clock and stay even while you can see it. But phones pause a tab when the screen locks or when you switch apps, and then it stops.
Test your own metronome app
- Set the app to 100 BPM. Put the phone next to a computer and record 2 to 5 minutes with a free audio editor, such as Audacity.
- Lock the phone's screen halfway through, if you use it that way.
- Zoom in on the recording. Every click should be there, and the gaps should look the same from start to end.
- For a quick check by ear, start two metronomes at the same tempo at the same moment. If one slowly pulls ahead, one of them drifts.
A recording through a microphone adds a little noise of its own, so look for gaps that are clearly different, not for tiny changes.
Questions
Do metronome apps drift?
Some do. An app that times clicks with an ordinary timer can slowly speed up or slow down, and it can skip when the screen is off. An app that places clicks on the audio clock should not drift. Ours drifted 0.001 ms per minute in a 30-minute test.
Are online metronomes accurate?
A good one is even while its tab is open and the screen is on, because it can plan clicks on the audio clock. Phones pause browser tabs when the screen locks, so for long practice with the screen off, use an app.
Does Bluetooth make a metronome late?
Yes, by a fixed amount that depends on the headphones or speaker. The clicks stay even, but they reach your ears later than the screen shows. A wired speaker or the phone's own speaker avoids it.
Is a phone metronome good enough for a drummer?
If it keeps time on the audio clock and keeps playing with the screen off, yes. In our test the gaps between clicks changed by less than 0.02 ms, a hundred times inside our own 2 ms pass mark.