Beat Frequency Calculator

Work out beat frequency instantly with clear inputs, formula shown and shareable results.

About Beat Frequency Calculator

Two close frequencies interfere to produce a slow amplitude pulsation at their difference frequency. 440 Hz against 444 Hz beats four times a second - one beat every 0.25 s - and the perceived pitch sits at the average, 442 Hz. Piano tuners use exactly this: they slow the beats to zero.

Formulas

Beat frequency

f(beat) = |f1 - f2|

Musical interval

cents = 1200 log2(f2 / f1)

Worked example

With the default values below, Beat Frequency Calculator returns Beat Frequency of 4.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

First frequencyminimum 0 Hz: 440 Hz
Second frequencyminimum 0 Hz: 444 Hz

Results

Beat Frequency: 4.000 Hz
Time Between Beats: 0.2500 s
Perceived Pitch: 442.00 Hz
Interval In Cents: 15.67

Step by step

1Values used
2Beat frequency
3Musical interval
4Beat Frequency= 4.000 Hz
5Time Between Beats= 0.2500 s
6Perceived Pitch= 442.00 Hz
7Interval In Cents= 15.67

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or fees or charges into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why do beats disappear when in tune?

Because the difference frequency falls to zero. As tuning improves the beats slow until they stop, which is far more sensitive than judging pitch directly.

What if the frequencies are far apart?

Above about 20 Hz difference the beating is no longer heard as pulsation but as roughness, and then as two separate tones.