Find the tempo.
Make the loop fit.
Turn a loop length into BPM. Match a new tempo, compare time-stretching with repitching, and keep a timing sheet for your sampler or DAW.
One loop. Two approaches.
Numbers only: no audio processing, audio upload, or saved inputs. Check your sampler’s parameter conventions before applying a percentage.
How to calculate BPM from a sample loop
A loop’s length only gives a tempo when you know its musical length. Multiply the bar count by the quarter-note beats per bar, then multiply by 60 and divide by seconds. Four bars of 4/4 contain 16 quarter notes: an 8-second loop is 120 BPM. The same audio interpreted as two bars is 60 BPM; eight bars makes it 240 BPM. Listen to the phrasing to choose the right interpretation.
For a sample-frame count, first divide frames by the file’s original sample rate to find seconds. A stereo frame contains one sample for each channel, so do not double the frame count. The calculator assumes a constant tempo and a clean loop boundary; a reverb tail or loose trim changes the answer.
Time-stretch or repitch?
To keep the same bar count at a new tempo, target seconds = quarter-note beats × 60 ÷ target BPM. Time-stretching aims to reach that duration while preserving pitch; its sound depends on the algorithm and material. This page does not predict artifacts.
Repitching changes playback speed, moving tempo and pitch together. Playback rate = target BPM ÷ source BPM. Pitch change in equal-tempered semitones = 12 × log₂(playback rate). Double speed gives half the duration and a pitch one octave higher. Half speed gives twice the duration and a pitch one octave lower.
Rate percentage and duration percentage are reciprocals. An 8-second loop at 120 BPM becomes 7.5 seconds at 128 BPM: playback rate is 106.667% of original, while output duration is 93.75% of original. Some devices label these controls differently. Match the meaning, rather than copying a number just because it says “stretch.” Rounded semitone and fine-tune settings approximate the exact ratio.
What does 6/8 mean here?
The bottom number names the note value; it does not redefine BPM in this tool. A 6/8 bar has six eighth notes, equal to three quarter notes. If your session uses dotted-quarter BPM, multiply that tempo by 1.5 before entering it here. Timing-table triplets are three equal notes in the time of two of the named note; dotted notes last 1.5 times the straight value.
Sources & scope
- Ableton Live manual: Audio Clips, Tempo, and Warping — loop-length interpretation, half/double tempo ambiguity, and Re-Pitch playback behavior.
- UNSW Music Acoustics: Note names, MIDI numbers and frequencies — equal-tempered semitone frequency ratios.
Sources checked October 19, 2026. Timing and ratio formulas are shown above for inspection. General sampler/DAW reference, with no device-specific compatibility claim or affiliate links. See our Privacy Policy.
Working on the hardware too? Visit the Octatrack Parts Guide.