PWM Resolution Calculator

Work out pwm resolution instantly with clear inputs, formula shown and shareable results.

About PWM Resolution Calculator

PWM resolution is the timer clock divided by the PWM frequency, capped by the timer width. That is a hard trade: at 80 MHz a 20 kHz carrier gives 4,000 steps (about 12 bits), but pushing to 200 kHz leaves only 400 steps, under 9 bits.

Formula

PWM resolution

steps = timer clock / PWM frequency, capped at 2^bits; resolution in bits = log2(steps)

Worked example

With the default values below, PWM Resolution Calculator returns Effective resolution of 11.97. Change any input above and every figure here is recalculated in your browser.

Inputs used

Timer clock: 80 MHz
PWM frequency: 20 kHz
Timer width: 16 bits

Results

Effective resolution: 11.97 bits
Duty cycle steps: 4,000 steps
Duty cycle step size: 0.02500% %
Maximum frequency for 10-bit resolution: 78.13 kHz

Step by step

1Values used
2PWM resolution
3Effective resolution= 11.97 bits
4Duty cycle steps= 4,000 steps
5Duty cycle step size= 0.02500 %
6Maximum frequency for 10-bit resolution= 78.13 kHz

Assumptions and limits

The result is derived only from the 3 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 5 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 high PWM frequencies lose resolution?

Each PWM period contains fewer timer ticks, and the tick count is the number of distinct duty cycles available.

How do I get both high frequency and resolution?

Use a faster timer clock, a hardware high-resolution PWM peripheral, or dithering between adjacent duty values across successive cycles.