Quick answer
Frequency is the reciprocal of period: f = 1 ÷ T and T = 1 ÷ f. A period of 0.02 s corresponds to a frequency of 50 Hz.
Choose the direction and enter a value. The calculator returns the other quantity.
Related tools: Wavelength to Frequency Calculator: Frequency of an electromagnetic wave from its wavelength in vacuum. Frequency Converter: Convert hertz, kilohertz, megahertz, gigahertz and rpm. Period Calculator: Predicted next period, ovulation and fertile window from your last period.
How to use the Period to Frequency Calculator
- Choose convert: Period → frequency and Frequency → period.
- Enter value (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Convert | Choose one: Period → frequency; Frequency → period | Starts at Period → frequency |
| Value | A number. Seconds for a period, hertz for a frequency | > 0 |
Formula and method
Formula
f = 1 ÷ T; T = 1 ÷ f
IEEE-754 double precision; shown to at most 6 decimal places.
Reciprocal relation.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Convert = Period → frequency; Value = 0.02.
| Result | Value |
|---|---|
| Frequency (Hz) | 50 |
Example 2
Inputs: Convert = Frequency → period; Value = 50.
| Result | Value |
|---|---|
| Period (s) | 0.02 |
The first line is the headline result (frequency (Hz)). IEEE-754 double precision; shown to at most 6 decimal places.
Everyday values
60 Hz mains has a period of 16.67 ms, a 1 kHz tone 1 ms and a 2.4 GHz Wi-Fi carrier about 0.417 ns. Longer periods mean lower frequencies.
Units
A period in seconds gives a frequency in hertz; in milliseconds, kilohertz. The value must be positive because zero would mean infinite frequency.
How the result changes with value
Holding every other input at the first worked example, this table changes only value. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Value | Frequency (Hz) |
|---|---|
| 0.01 | 100 |
| 0.02 | 50 |
| 0.04 | 25 |
| 0.08 | 12.5 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Value: entering "0" shows "Value must be greater than 0." beside that field and no result.
Choosing between the Period to Frequency Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Wavelength to Frequency Calculator](/converters/wavelength-to-frequency/) | wavelength | Frequency |
| [Frequency Converter](/converters/frequency-converter/) | value, from and to | Revolutions per minute (rpm) → Hertz (Hz) |
| [Period Calculator](/time/period-calculator/) | first day of last period, average cycle length and period length | Next period starts |
| [Payback Period Calculator](/business/payback-period/) | initial investment and annual cash flow | Payback period |
| [Relative Frequency Calculator](/statistics/relative-frequency/) | counts | Relative frequencies |
Background: unit conversion
Many customary units are defined exactly in terms of metric ones: since the 1959 International Yard and Pound Agreement an inch is exactly 2.54 cm and a pound is exactly 0.45359237 kg (NIST SP 811 lists these). So most length and mass conversions are exact apart from the rounding of the displayed result.
To convert, multiply the value by the source unit's factor to reach the base unit, then divide by the target unit's factor; the unit table on this page lists every factor used. Temperature and fuel economy are the exceptions, because they are not simple multiples.
Assumptions and limitations
- Value must be positive
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for value to confirm this.
Frequently asked questions
What is the period of 1 MHz?
1 MHz is one million cycles per second, so the period is 1 ÷ 1,000,000 = 1 microsecond.
What is the frequency of a 0.5 s period?
A period of 0.5 s gives f = 1 ÷ 0.5 = 2 Hz.
Is angular frequency the same?
No. Angular frequency ω = 2πf is in radians per second, while this page converts between period and frequency in hertz.
What does the Period to Frequency Calculator calculate?
Frequency from period, or period from frequency. It returns Frequency (Hz).
What formula does the Period to Frequency Calculator use?
f = 1 ÷ T; T = 1 ÷ f. Reciprocal relation.
What do I need to enter in the period to Frequency Calculator?
You enter Convert and Value.
What does the “Convert” option change?
It sets how the period to Frequency is worked out. The choices are Period → frequency and Frequency → period.
What is an example of a period to Frequency result?
With convert Period → frequency and value 0.02, the frequency (Hz) is 50.
Related calculators
- Wavelength to Frequency Calculator — Frequency of an electromagnetic wave from its wavelength in vacuum.
- Frequency Converter — Convert hertz, kilohertz, megahertz, gigahertz and rpm.
- Period Calculator — Predicted next period, ovulation and fertile window from your last period.
- Payback Period Calculator — Time to recover an investment from steady cash flow.
- Relative Frequency Calculator — Relative frequencies and percentages from counts.
Sources
- OpenStax, University Physics Volume 1 (Rice University): mechanics
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.