Song length calculator: bars and BPM to minutes

A song length calculator converts tempo, time signature and bar count into minutes and seconds. In 4/4 one bar lasts 240 ÷ BPM seconds, so 32 bars at 120 BPM is exactly 64 seconds (1:04), and a 3:30 song at 140 BPM holds 122.5 bars. Enter your own BPM in the tool above, or read the answer off the tables below.

Song time calculator, music duration calculator, BPM to time calculator: different names, one calculation (beats per bar × bars × 60 ÷ BPM). Unsure of the tempo? Run the track through the BPM detector first.

BPM to seconds: the formula

BPM means beats per minute, so one beat lasts 60 ÷ BPM seconds. A bar is that beat times the beats per bar; a section is the bar times the bar count.

Going the other way, bars = seconds × BPM ÷ 240 in 4/4: a 30-second ad bed at 128 BPM is exactly 16 bars, which is why 128 is such a convenient sync tempo. For the same beat in milliseconds, the delay & reverb time calculator does the division for every note value.

Bars to seconds table (4/4)

Length of 1, 4, 8, 16 and 32 bars at common tempos, with mm:ss where a section runs to a minute or more.

Halve the BPM and the time doubles: 8 bars at 70 BPM lasts as long as 16 bars at 140 BPM, which is why a 70 BPM half-time groove and a 140 BPM trap pattern can be the same drums written two ways (see hip hop key and tempo). Typical tempos per style: BPM by genre.

How many bars fit in 30 s, 60 s, 2:30 and 3:30

The reverse question comes up for ads, intros, radio edits and DJ transitions. In 4/4, bars = seconds × BPM ÷ 240. A fraction means the clock runs out mid-bar: round down and fill the rest with a pickup, a tail or silence.

Worked example: a 3:30 song at 140 BPM is 122.5 bars. 122 full bars take 209.14 s, so the last 0.86 s is a tail. A 4-bar intro, two 16-bar verses, three 8-bar hooks, an 8-bar bridge and an 8-bar outro come to 84 bars, leaving 38.5 bars (66 s) for a longer intro or an extra hook.

Time signature calculator: 3/4, 6/8 and odd meters

The time signature changes how many beats make a bar, not how long a beat is. At 120 BPM a beat is 0.5 s in any meter: a 4/4 bar is 2 s, a 3/4 bar is 1.5 s, a 5/4 bar is 2.5 s. The trap is compound meter. Most DAWs keep the BPM tied to the quarter note whatever the signature says, so a 6/8 bar at 120 BPM is three quarter notes (1.5 s); a drummer feels it as two dotted-quarter pulses, and a click set to eighths counts six. The calculator multiplies whatever beat your BPM counts by the number of those beats per bar, so decide which pulse your BPM refers to and enter that many.

Worked example: a waltz at 90 BPM in 3/4 has 2-second bars (3 × 60 ÷ 90), so 32 bars is 64 s, the same as 32 bars of 4/4 at 120 BPM. Repitching a sample moves its bar length too: the pitch & semitone calculator gives the new BPM, the tape / vari-speed calculator the same in percent.

Album length calculator: add the tracks, then the gaps

Album length is addition in minutes and seconds plus the silence between tracks. On a CD the default gap is 2 seconds and a CD-R holds about 80 minutes. Streaming has no enforced gap, so the only silence is what you leave in the files. Vinyl is the tight format: cutting engineers commonly quote around 20 minutes a side for a 12-inch LP at 33⅓ rpm before level has to give way to playing time.

1. Convert each track to seconds. 3:12 = 192 s, 2:58 = 178 s, 3:45 = 225 s, 4:02 = 242 s, 3:30 = 210 s, 2:47 = 167 s, 3:55 = 235 s, 3:18 = 198 s, 4:10 = 250 s, 3:04 = 184 s.
2. Add them up. 2081 s = 34:41 across 10 tracks, an average of 3:28 per track.
3. Add the gaps. Nine gaps × 2 s = 18 s, so the CD runs 34:59; on streaming the album shows as 34:41. It fits one CD and two vinyl sides of roughly 17 minutes each.

Where song lengths sit today is covered in average song length. To check a tempo by ear while you plan sections, the online metronome runs in the same tab.

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