Duty Cycle Calculator
Calculate duty cycle from on time and off time.
Duty Cycle Formula
Duty cycle = on time ÷ (on time + off time) × 100.
What Does Duty Cycle Mean?
Duty cycle is the percentage of one operating cycle that a signal, switch or device remains on. It is commonly used with PWM signals, motors, heaters, LEDs and switching electronics.
Example Calculation
If a signal stays on for 3 milliseconds and off for 7 milliseconds, one complete cycle lasts 10 milliseconds. Duty cycle = 3/10 × 100 = 30%.
Factors and Interpretation
A higher duty cycle means a larger fraction of time in the active state. For many PWM-controlled loads, increasing duty cycle raises average delivered power, but the exact relationship depends on the load, switching method and supply conditions. On-time and off-time must use the same time unit.
Frequently Asked Questions
Is 50% duty cycle equal on and off time?
Yes. A 50% duty cycle means the signal is on for half of each cycle.
Can duty cycle exceed 100%?
No. By definition it ranges from 0% to 100%.
Do I need frequency to calculate duty cycle?
Not when on-time and off-time are known. Frequency can be derived separately from the total period.
Related Tools
Formula and Practical Limits
Duty cycle is on-time divided by total cycle time, expressed as a percentage. The same duty cycle can occur at different frequencies, so it does not by itself describe switching rate, pulse energy or thermal response.