About this tool
Type in a time signature (beats per bar over a note value) and a tempo in BPM, and this calculator returns how long a single bar lasts in seconds — handy for lining up loops, setting delay times or planning arrangements in a DAW. It runs entirely in your browser.
The BPM is counted in quarter notes, the usual DAW convention. Bar duration = beatsPerBar × (60 ÷ BPM) × (4 ÷ denominator); the final factor scales the quarter-note pulse to the actual beat unit. So 4/4 at 120 BPM gives 4 × 0.5 × 1 = 2 seconds per bar, while 6/8 at the same tempo gives 6 × 0.5 × 0.5 = 1.5 seconds. Beat duration is the same expression without the beats-per-bar factor, bars per minute is 60 ÷ bar duration, and beats per second is 1 ÷ beat duration.
Enter an optional length in seconds and it also tells you how many bars fit that span (length ÷ bar duration) — useful for filling a fixed video slot or a set-length loop. All figures update live as you type.