What is a time signature?

A time signature has two numbers: the top (numerator) tells how many beats are in each bar, and the bottom (denominator) tells which note value equals one beat. For example, 4/4 means four quarter-note beats per bar.

What does the equivalency ratio mean?

The ratio shows how many bars of the target time signature contain the same total duration as one bar of the source. A ratio of 1.33 means one source bar equals 1.33 target bars in duration.

What is the difference between simple and compound meter?

Simple meters (2/4, 3/4, 4/4) divide beats into two equal parts. Compound meters (6/8, 9/8, 12/8) divide beats into three equal parts, so the beat feels like a dotted note.

Why does 6/8 feel different from 3/4 even though both have six eighth notes per bar?

In 6/8 the primary beats are dotted quarter notes (groups of three eighth notes), giving a two-in-a-bar feel. In 3/4 the primary beats are quarter notes (groups of two eighth notes), giving a three-in-a-bar feel.

How is the BPM beat duration calculated?

Beat duration in milliseconds = (60 000 ms / BPM) × (4 / denominator). This scales the quarter-note pulse to the actual note value of the beat in that time signature.

Time Signature Converter

Name: Time Signature Converter
Availability: InStock
Author: Nham Vu

Enter two time signatures and an optional BPM to see how many bars of one equal one bar of the other, plus beat durations in milliseconds.

Time Signature Converter

Source Meter

Target Meter

Tempo (BPM) — optional

Equivalency

4/4

Source

1.33

bars of target

3/4

Target

Source bar duration

—

ms per bar

Target bar duration

—

ms per bar

Source beat duration

—

ms per beat

Target beat duration

—

ms per beat

Beat Grid (LCM bars)

Source

Target

Summary

Enter two time signatures and an optional BPM to see how many bars of one equal one bar of the other, plus beat durations in milliseconds.

How it works

Select the numerator and denominator for your source time signature (e.g. 4/4).
Select the numerator and denominator for your target time signature (e.g. 3/4).
Optionally enter a BPM to calculate bar and beat durations in milliseconds.
Read the equivalency ratio — how many target bars fit in one source bar.
Use the beat grid to see how individual beats map across both meters.

Use cases

Understand how a passage in 6/8 relates to the same material in 3/4.
Calculate how many 5/4 bars fit within a 4/4 loop length.
Convert conductor cues between compound and simple meters.
Find the beat duration in milliseconds when syncing music to video at a given BPM.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu