Duty Cycle Calculator

The duty cycle of a signal is the percentage of each cycle that the signal is active — a key value in electronics, PWM motor control, and power systems. Enter your Pulse Width (On Time) and Period (Total Cycle Time) into the Duty Cycle Calculator to get the Duty Cycle percentage, along with the Off Time and Frequency. Alternatively, enter a Frequency in Hz to have the period calculated automatically. Also try the Form Factor Calculator.

ms

Duration the signal is 'on' during each cycle

ms

Complete duration of one cycle (on + off time)

Hz

Frequency in Hz (will calculate period automatically)

Results

Duty Cycle

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Off Time

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Frequency

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Frequently Asked Questions

What is the duty cycle?

The duty cycle is the percentage of time a periodic signal is 'on' during each complete cycle. It's calculated as (pulse width ÷ period) × 100%. A 50% duty cycle means the signal is on for half the time and off for half the time. See also our Signal-to-Noise Ratio (SNR) Calculator.

How do I calculate the duty cycle from the pulse width?

To calculate duty cycle, divide the pulse width (on time) by the total period and multiply by 100. For example, if pulse width is 15ms and period is 40ms, the duty cycle is (15÷40) × 100 = 37.5%.

Why is the duty cycle useful?

Duty cycle is crucial in electronics for PWM control, motor speed control, power regulation, and LED brightness control. It's also important in automotive for fuel injector timing and engine diagnostics.

What does it mean to have a duty cycle of 30%?

A 30% duty cycle means the signal is 'on' for 30% of each cycle and 'off' for 70%. For a 100ms period, this would be 30ms on and 70ms off. You might also find our Baud Rate Calculator useful.

What is the duty cycle of a pulsed radar that is on for 10 ms every second?

For a radar on for 10ms every second (1000ms period), the duty cycle is (10÷1000) × 100 = 1%. This low duty cycle helps reduce power consumption while maintaining functionality.

Can I use frequency instead of period to calculate duty cycle?

Yes, you can use frequency. First convert frequency to period using Period = 1 ÷ Frequency, then calculate duty cycle normally. This calculator automatically handles both inputs.

What's the relationship between duty cycle and average power?

For PWM signals, average power is proportional to duty cycle. A 25% duty cycle delivers approximately 25% of maximum power, making it useful for controlling motor speeds and LED brightness.