BPM is the one number that determines the shape of a beat-matched edit before you have chosen a single clip. Knowing it in advance is the difference between picking a track that suits your footage and discovering at the end that it does not.
What BPM actually is
Beats per minute: how many pulses there are in a minute of music — the thing you tap your foot to. Divide by 60 for beats per second, multiply by the length of your video, and you have the number of cut points available.
| BPM | Beats/sec | Beats in 30s | Feels |
|---|---|---|---|
| 70 | 1.17 | 35 | Slow, spacious |
| 90 | 1.50 | 45 | Relaxed |
| 120 | 2.00 | 60 | The default — pop, house |
| 140 | 2.33 | 70 | Driving, energetic |
| 174 | 2.90 | 87 | Frantic |
Four ways to find it
| Method | Accuracy | Speed | Use when |
|---|---|---|---|
| Tap tempo | ±2 BPM | 15 seconds | Choosing between tracks |
| A BPM database | Exact | A minute | The track is commercially released |
| Your editor's detection | Exact | Instant | The track is already imported |
| Counting by hand | ±3 BPM | A minute | No tools available |
- Tap tempo. Play the track and tap a key in time with the beat for about ten seconds. Any tap-tempo page or app will do it, and the average of twenty taps is close enough to choose by.
- A BPM database. Sites that index commercial releases — the ones DJs use — give the exact figure for anything released. Useless for library music, which is most of what you will legally be editing to: can you use copyrighted music in reels?
- Detection in the editor. The most useful, because it gives you the actual beat positions rather than just the average tempo. Beat detection explained covers how that works and where it goes wrong.
- By hand. Count beats for fifteen seconds and multiply by four. Crude, always available, and accurate enough to tell 90 from 140.
Most library sites list the BPM on the track page, which makes choosing by tempo a filter rather than a task — worth using, because picking the track first and discovering the tempo afterwards is doing it backwards.
The half-time and double-time trap
The most common reason two tools disagree, and the most common reason a detector "gets it wrong" when it has not. A track at 140 BPM can be heard, legitimately, as 70 — the beats are still there, you are just counting every other one.
- Both numbers are correct. 70 and 140 describe the same music at different counting resolutions.
- Drum and bass is the classic case. Written as 174, felt as 87. Detectors report either.
- Trap and hip-hop too. A 140 BPM trap beat feels like 70 because the snare lands on every other beat.
- It only matters for cut density. At 140 cutting every second beat, you get the same edit as 70 cutting every beat.
Choosing a tempo for your footage
This is the part BPM is actually for. Tempo decides how long each shot is on screen, and different footage needs different amounts of time to be legible.
| Footage | Tempo | Cut on | Shot length |
|---|---|---|---|
| Product detail, food, text | 80–100 | Every 2nd beat | 1.2–1.5s |
| General b-roll, lifestyle | 110–125 | Every 2nd beat | ~1.0s |
| Motion — sport, driving, dance | 125–140 | Every beat | 0.4–0.5s |
| Stills and slideshows | 90–110 | Every 2nd or 4th | 1.1–2.5s |
| Talking or faces | 100–120 | Every 4th beat | ~2.0s |
The rule underneath the table: a shot has to be on screen long enough to be understood. Motion reads almost instantly; a detail shot or a still needs around a second. Choosing a 174 BPM track for product photography produces shots of a third of a second that nobody can parse — see photo slideshow reels for the slowest end of this.
Working out what you need before you shoot
The practical payoff. Once you know the tempo and the length, you know the shot count, and the shot count is what tells you whether your folder is deep enough.
shots = (BPM / 60) x seconds / beats-per-cut
120 BPM, 30s, every 2nd beat:
(120 / 60) x 30 / 2 = 30 shots
140 BPM, 20s, every beat:
(140 / 60) x 20 / 1 = 47 shotsForty-seven shots is more than most people have, which is the honest reason so many fast-cut edits repeat the same four clips. Filming b-roll on a phone is how the folder gets deep enough to support the tempo you wanted.
Why the average is not enough
BPM is one number describing a whole track, and real music does not hold perfectly still. A live drummer pushes and drags, a track can change tempo between sections, and an intro often has no percussion at all.
Which is why a tempo figure is useful for *choosing* a track and insufficient for *cutting* one. Cutting needs the actual beat positions — a list of timestamps — because a cut placed by arithmetic at exactly 0.5-second intervals will drift out of sync with a human performance within about fifteen seconds.
In Easy Reels that is the distinction between the number and the waveform: beats are detected as positions, you can drag, add or delete any of them, and a minimum-gap setting stops two closely-spaced beats producing a shot nobody sees. Use BPM to pick the song; use the detected beats to cut it.