Duty Cycle to Time
Convert duty cycle percentage to on/off times. Enter circuit values to calculate the selected electrical quantity.
PWM Specifications
Electronics guide · Signals, timing, and radio frequency
About Duty Cycle to Time Calculator
This calculator converts a pulse's duty cycle and total period into its on-time and off-time. It also reports frequency from the period. These values describe a repeating signal and are helpful when reviewing a PWM specification or timing waveform.
Signal and RF calculations connect frequency, period, wavelength, bandwidth, sampling, impedance, and ratios. Results often assume ideal propagation or a simplified signal model; real cables, antennas, clocks, and converters can add losses, tolerances, reflections, and environmental effects.
How to Use This Tool
- 1.Enter the duty cycle as a percentage from 0 to 100.
- 2.Enter the total signal period in milliseconds, which must be greater than zero.
- 3.Calculate and read the pulse on-time, off-time, and frequency. Check that on-time plus off-time equals the entered period.
Technical Details to Check
1.Frequency and time are linked
For a periodic signal, period is the reciprocal of frequency. Convert prefixes carefully: hertz, kilohertz, megahertz, and gigahertz differ by powers of one thousand.
2.Propagation depends on the medium
Wavelength is related to frequency and propagation speed. A free-space estimate differs from wavelength in a cable or material where the signal travels more slowly.
3.Logarithmic ratios need a reference
Decibels and related units describe ratios, often with a stated reference such as dBm. Check whether the tool is converting power, voltage, or a normalized ratio before using the value.
4.Sampling is not reconstruction quality
A sampling condition can help assess whether a signal's frequency content is representable, but real filters, clock jitter, noise, and system bandwidth also affect sampled data.
How the Calculation Works
On-time Ton = period × (duty cycle ÷ 100). Off-time Toff = period − Ton. Frequency in hertz is 1 ÷ period in seconds; because the input period is in milliseconds, the tool uses 1000 ÷ period(ms). A duty cycle is the on portion divided by the full period.
Worked Example
At 50% duty cycle and a 20 ms period, the on-time is 10 ms and the off-time is 10 ms. The frequency is 50 Hz.
Where This Tool Can Help
Translate PWM timing values, check a pulse-width specification, and understand how duty percentage changes the active portion of a repeating signal.
Converting signal units
Move between frequency, time, wavelength, or power representations while keeping the source unit and reference clear.
Checking a communications setup
Estimate baud timing, clock tolerance, or signal ratios, then compare the result with the transceiver and protocol requirements.
Planning an RF or antenna estimate
Use a frequency-based result as a starting point and account separately for material, antenna geometry, matching, and the surrounding environment.
Reviewing sampled signals
Check a theoretical sampling relationship before testing the actual signal path, filters, converter limits, and clock quality.
Tips for More Reliable Results
- Write down the frequency, time, impedance, and reference units before entering a value.
- Check whether the formula assumes free-space propagation, ideal components, or a matched load.
- For dB values, identify the reference and whether the underlying quantity is power or amplitude.
- Compare theoretical results with datasheets, measured behavior, and the operating frequency range.
Limitations and Assumptions
This is an ideal timing calculation. It does not model rise time, fall time, jitter, dead time, load behavior, or timer resolution. The tool accepts a period in milliseconds, so convert other time units before entering them.
Signal calculations describe a model, not a complete measurement of a physical system. Propagation medium, component tolerance, noise, impedance mismatch, bandwidth, and instrument limitations may not be represented by the inputs.
Frequently Asked Questions
Can duty cycle be above 100%?
No. It is the on portion as a share of the full period and ranges from 0% to 100%.
What happens at 0% or 100%?
The ideal signal is always off or always on, respectively.
How do I get frequency from period?
Convert the period to seconds and take its reciprocal; this page also reports it from milliseconds.
Is wavelength always the free-space value?
No. The medium changes propagation speed, so a cable or material can have a shorter wavelength than free space.
Does a sampling calculation guarantee a clean digital signal?
No. Filtering, noise, clock accuracy, converter performance, and signal bandwidth also matter.