〰️ Frequency Calculator
Calculate frequency from period using f = 1/T, or from wavelength and wave speed using v = fλ. This tool supports multiple units (Hz, kHz, MHz, seconds, milliseconds, meters, etc.) and provides a step-by-step breakdown.
What Is Frequency?
Frequency is the number of occurrences of a repeating event per unit of time. In physics, it usually refers to the number of wave cycles that pass a fixed point in one second. The SI unit for frequency is the Hertz (Hz), which is equivalent to one cycle per second.
Frequency is inversely related to period (T), which is the time it takes for one complete cycle:
f = 1 / T
For waves, frequency is also related to wavelength (λ) and wave speed (v):
v = f · λ
or f = v / λ and λ = v / f
These relationships are fundamental in many fields, including acoustics, optics, radio communications, and electrical engineering.
How to Calculate Frequency
There are two common ways to calculate frequency, depending on the information you have:
- From Period: If you know the time for one cycle (T), use f = 1/T.
- From Wavelength and Speed: If you know the wave's speed (v) and wavelength (λ), use f = v/λ.
For example, a signal that repeats every 0.02 seconds has a frequency of:
f = 1 / 0.02
f = 50 Hz
A sound wave with a speed of 343 m/s and a wavelength of 0.78 m has a frequency of:
f = 343 / 0.78
f ≈ 440 Hz
Why Use This Calculator?
- Two modes: Calculate frequency from period or from wavelength and speed.
- Flexible units: Supports Hz, kHz, MHz, seconds, milliseconds, meters, and more.
- Step-by-step breakdown: See exactly how the calculation is done.
- Free & private: No registration, no data storage — all calculations are done in your browser.
❓ Frequency Calculator FAQ
What is the formula for frequency?
The two most common formulas are f = 1/T (frequency from period) and f = v/λ (frequency from wave speed and wavelength).
What is the relationship between frequency and period?
Frequency and period are inverses of each other: f = 1/T and T = 1/f. A higher frequency means a shorter period.
What is the unit of frequency?
The SI unit of frequency is the Hertz (Hz), which is equal to one cycle per second (s⁻¹).
How do I convert kHz to Hz?
Multiply by 1,000. For example, 5 kHz = 5,000 Hz.
How do I convert MHz to Hz?
Multiply by 1,000,000. For example, 100 MHz = 100,000,000 Hz.
What is the frequency of AC power?
In the United States and parts of the Americas, AC power is 60 Hz. In most other countries, it is 50 Hz.
What is the frequency range of human hearing?
Human hearing typically ranges from 20 Hz to 20,000 Hz (20 kHz).
How accurate is this calculator?
This calculator uses the exact standard formulas. Accuracy depends on the precision of your input values. You can adjust the decimal precision in the results.
Is this calculator free?
Yes, this calculator is completely free to use. No registration or personal data storage is required.
What is the difference between frequency and angular frequency?
Frequency (f) is measured in Hertz (cycles per second). Angular frequency (ω) is measured in radians per second and is related by ω = 2πf.