HesapHanem

Frequency to Period Calculator

Convert frequency to period.

How it is calculated

The period of a repeating signal is the inverse of its frequency: T = 1 / f. Frequency f is entered in hertz (cycles per second) and the period T comes out in seconds, milliseconds, microseconds or nanoseconds, whichever fits. The frequency must be greater than zero. The result is rounded to two decimals in that unit: 50 Hz is displayed as 20.00 ms, 1 kHz as 1.00 ms, 1 MHz as 1.00 µs and 0.5 Hz as 2.00 s. Enter kilohertz or megahertz values as hertz (1 kHz = 1000 Hz, 1 MHz = 1,000,000 Hz).

Worked example

A signal repeats 4 times each second, so f = 4 Hz. The period is T = 1 / 4 = 0.25 s, which the tool shows as 250.00 ms. Each cycle takes a quarter of a second, and doubling the frequency to 8 Hz would halve the period to 0.125 s, shown as 125.00 ms.

Try this example →

Common mistakes

  • Entering kilohertz or megahertz as if it were hertz; 50 kHz must be typed as 50000.
  • Overlooking the unit label: the answer switches between s, ms, µs and ns depending on how short the period is.
  • Reading a tiny period such as 1.00 µs as zero when it is just very short.
  • Typing zero frequency; the period of a constant signal is undefined.
  • Confusing frequency in hertz with angular frequency in radians per second, which is 2π times larger.

About this calculator

This calculator applies the inverse relationship T = 1/f, where period (T, in seconds) is the time for one complete wave cycle and frequency (f, in Hertz) is how many cycles occur per second — doubling the frequency always halves the period, and vice versa. It works across any oscillating signal, from AC electrical current at 50 or 60 Hz to a microprocessor clock running at gigahertz speeds.

Electrical engineers checking a circuit's timing, programmers setting up a timer or PWM signal that's specified in Hertz but needs to be coded in milliseconds, and physics students converting between the two units in wave problems all use this same formula.

Was this helpful?

You can pick up to 3 reactions.

Comments (1)

  • Editorial team

    Mains electricity makes a good test: at 50 Hz one cycle lasts 20.00 ms and at 60 Hz about 16.67 ms. The result switches to milliseconds, microseconds or nanoseconds as the period gets shorter, so a 1 MHz signal reads 1.00 µs rather than a row of zeros. Check that the frequency is in hertz, not kilohertz, before you trust the number. What kind of signal are you working with?

Popular calculators

Loan Calculator

Monthly payment, total interest and full amortization schedule.

Percentage Calculator

Percent change, percent of, and ratio calculations.

Discount Calculator

Calculate final price, savings, and discount amount.

BMI Calculator

Body mass index from height and weight (metric or imperial).

Age Calculator

Compute your exact age in years, months and days from a birth date.

Compound Interest Calculator

Calculate the final amount and interest earned with compounding.

All Calculators