PWM Duty Cycle Calculator

Summary

Pulse Width Modulation (PWM) controls the average power delivered to a load by switching a signal on and off at a fixed frequency. The duty cycle — the ratio of on-time to total period — determines the effective output voltage and governs motor speed, LED brightness, and switching converter efficiency. This calculator takes any two of pulse width, period, or frequency and computes all derived values instantly.

How it works

1. Enter the supply voltage (Vcc) and select the time unit (µs, ms, or s).
2. Enter the pulse width (on-time) and the total period, or switch to frequency mode and enter frequency in Hz or kHz.
3. Click Calculate to see duty cycle %, on-time, off-time, period, frequency, and average output voltage.
4. Adjust any value and recalculate — the duty cycle bar updates to reflect the new ratio.
5. Use Reset to clear all fields and start a new calculation.

Use cases

• Size PWM parameters for a DC motor speed controller.
• Set LED dimming level for a constant-current driver.
• Verify switching frequency and duty cycle for a buck or boost converter.
• Calculate average output voltage of a PWM-driven H-bridge.
• Check on-time and off-time constraints for a MOSFET gate driver.
• Teach or learn PWM theory with live numeric feedback.

Frequently Asked Questions