BPM to Hz Converter for Tempo-Synced LFO Rates in a DAW

Setting an LFO Rate in Hertz from Your Project Tempo

Plenty of modulation sources refuse to talk to the host clock. A vintage-style tremolo, a hardware filter pedal or a plugin with nothing but a rate knob all want a number in hertz, while the session around them is measured in beats per minute. Dividing the tempo by sixty gives the frequency of one cycle per quarter note, and every other note division falls out of that single figure as a multiplier.

Conversion factor: Hz = BPM ÷ 60. A project at 120 BPM gives 2 Hz, meaning one full LFO sweep per quarter note; halve the note value and the rate doubles, so eighth notes at that tempo need 4 Hz.

How the Divisions Stack Up

The Quarter Note Is Your Anchor

Tempo divided by sixty is always the quarter-note rate. Work that figure out once for the session and keep it near the desk — at 128 BPM it is 2.1333 Hz, and every tremolo, pan and sweep on the track scales from it.

Divisions Multiply, They Never Add

Halving the note value doubles the frequency. Eighths are twice the quarter rate, sixteenths four times, half notes half of it. A dotted eighth sits at two thirds of the plain eighth rate and an eighth triplet at three halves of it — the awkward pair worth checking.

Where Rhythm Turns into Tone

Below roughly 20 Hz an LFO is heard as pulsing. Push it past that and the ear stops counting cycles and hears sidebands instead, so the modulation becomes part of the timbre. Sixty-fourth notes at 120 BPM already sit at 32 Hz.

Dialling In a Tempo-Locked Modulation Rate

Enter the session tempo

Type the project's BPM into the left field. Half-tempo values such as 87.5 are accepted with either a dot or a comma as the decimal mark, so odd tempos from a sample-based track go straight in.

Read the quarter-note rate

The hertz figure updates on every keystroke and is shown to eight decimals, which is more resolution than most rate knobs expose. Round it to whatever the plugin field will actually accept.

Scale it to your note division

Double for eighths, quadruple for sixteenths, halve for half notes. Type the tempo again with the result in mind, or read the division table further down for the value you want.

Paste it into the rate field

The copy control lifts the bare number with no unit attached, which matters because plugin rate boxes usually reject anything with letters or spaces pasted into them.

Going the other way: if a pedal is already sweeping at a rate you like and you want to build a session around it, swap the direction or type the hertz figure into the right-hand field to find the matching tempo.

Note Divisions and Their Modulation Frequencies

Each row is one tempo and each column the LFO frequency for a full cycle of that note value. The dotted-eighth column is worth bookmarking: it drives most rhythmic delay and tremolo patterns, and its arithmetic is the least obvious.

Session tempo	Quarter note	Eighth note	Sixteenth note	Dotted eighth
90 BPM	1.5 Hz	3 Hz	6 Hz	2 Hz
100 BPM	1.6667 Hz	3.3333 Hz	6.6667 Hz	2.2222 Hz
120 BPM	2 Hz	4 Hz	8 Hz	2.6667 Hz
128 BPM	2.1333 Hz	4.2667 Hz	8.5333 Hz	2.8444 Hz
140 BPM	2.3333 Hz	4.6667 Hz	9.3333 Hz	3.1111 Hz
174 BPM	2.9 Hz	5.8 Hz	11.6 Hz	3.8667 Hz

Tempo In, Rate Knob Out

Both fields stay editable while you work, so a tempo change halfway through an arrangement takes one edit rather than a fresh calculation for every modulated track.

Reverse-Engineer a Pedal Setting

The swap control turns a hertz reading from a hardware unit back into the tempo it would lock to, useful when you are rebuilding a hardware chain inside the box.

Very Slow Sweeps Stay Readable

A pad LFO cycling once per eight bars lands well under a tenth of a hertz, and the display keeps enough decimals for that instead of collapsing it to zero.

Modulation Rate Questions from the Mix

What LFO rate gives one cycle per eighth note at 128 BPM?

Divide 128 by 60 for the quarter-note rate of 2.1333 Hz, then double it: 4.2667 Hz. If the plugin only accepts two decimals, 4.27 Hz shortens each cycle by 0.18 ms — about 1.5 ms per bar, inaudible on a tremolo but enough to smear the edge of a hard gated pattern across a long section.

Why do some plugins offer only a hertz rate instead of host sync?

Emulations of analogue hardware usually keep the original behaviour, where the LFO ran from its own oscillator with no knowledge of a song tempo. Some designers also leave sync out deliberately: a rate slightly off the grid produces the drifting phase relationship that makes an old tremolo or chorus sound alive rather than mechanical.

How do dotted and triplet divisions change the multiplier?

A dotted note lasts one and a half times its plain value, so its frequency is two thirds of the plain rate: at 120 BPM a dotted eighth cycles at 2.6667 Hz against the plain eighth's 4 Hz. A triplet squeezes three notes into the space of two, giving three halves of the plain rate, so an eighth triplet at that tempo runs at 6 Hz.

At what rate does an LFO become part of the timbre?

Around 20 Hz the ear stops resolving individual cycles and starts hearing the modulation as pitch content. Amplitude modulation at that speed generates sidebands either side of the carrier, so the result reads as a new tone rather than a rhythm — the basis of ring modulation. Sixteenth notes only reach 11.6 Hz even at 174 BPM, so tempo-locked rates rarely cross the line.

How does a tempo-matched delay time relate to a modulation frequency?

They are the same number seen from two sides. A quarter-note delay at 120 BPM is 500 ms, and 500 ms per cycle is exactly 2 Hz. Work out the frequency here and take its reciprocal in seconds for the delay box; at 128 BPM the quarter-note rate of 2.1333 Hz corresponds to 468.75 ms.