Answer first
What this calculator tells you
Convert the frequency of a radio or light wave into its wavelength and period. Turn a radio station or a Wi-Fi channel's frequency into the size of its wave. Formula: Wavelength = speed of light ÷ frequency; period = 1 ÷ frequency; c = 299,792,458 m/s. At the worked-example inputs, the wavelength (m) is 3. Holding every other input steady, moving frequency (mhz) from 80 to 120 moves the result from 2.5 to 3.7.
Transparent method
The formula
Turn a radio station or a Wi-Fi channel's frequency into the size of its wave.
Worked example
Example inputs
How to interpret the result
Waves that travel at the speed of light trade frequency for length: the higher the frequency, the shorter the wave. A radio station at 100 megahertz has a wavelength of about 3 meters, and each cycle takes 10 nanoseconds. That relationship sets the length of an antenna, and a Wi-Fi signal at 2.4 gigahertz is only about 12 centimeters long.
At the worked-example inputs the wavelength (m) is 3. It falls as frequency (mhz) increases.
These are textbook formulas for ideal conditions: no air resistance, no friction, gravity of 9.81 meters per second squared and gases that behave ideally. Real results differ, so treat them as first estimates and use the units the formulas expect (meters, kilograms, seconds).
Before you rely on it
What to check
Enter the frequency in megahertz. A value in kilohertz or gigahertz needs converting first, or the wavelength lands a thousand times off.
The common error
Where people go wrong with wavelength and frequency calculator
Using the speed of sound. Radio and light travel at about 300 million meters per second, nearly a million times faster than sound in air.
Sensitivity evidence
How frequency (mhz) changes the wavelength (m)
Holding every other input at the worked-example value, moving frequency (mhz) from 80 to 120 moves the wavelength (m) from 2.5 to 3.7: a spread of 1.2, or 42% of the worked-example result.
| Frequency (MHz) | Wavelength (m) | Period (nanoseconds) |
|---|---|---|
| 80 | 3.7 | 12.5 |
| 90 | 3.3 | 11.1 |
| 100worked example | 3 | 10 |
| 110 | 2.7 | 9.1 |
| 120 | 2.5 | 8.3 |
Step by step
The worked example, input by input
| Input | Value used | What it means |
|---|---|---|
| Frequency (MHz) | 100 | An FM radio station at 100 MHz is a typical example. |
| Wavelength (m) | 3 | |
| Period (nanoseconds) | 10 | |
Inputs, definitions and assumptions
Frequency (MHz)
An FM radio station at 100 MHz is a typical example. The prefilled worked-example value is 100.
How to use this calculator
- 1Verify the inputs. Gather frequency (mhz) from your own documents; the prefilled values are examples.
- 2Save a baseline. The worked example puts the wavelength (m) at 3. Store your own version of it as Scenario A.
- 3Test one change. Start with frequency (mhz), the input with the biggest effect here: moving frequency (mhz) from 90 to 110 takes the wavelength (m) from 3.3 to 2.7, a swing of 20% of the worked-example figure.
- 4Check the extremes. At half the example frequency (mhz) (50) the wavelength (m) is 6; at double (200) it is 1.5.
People also ask
Frequently asked questions
How do you calculate wavelength and frequency?
Wavelength = speed of light ÷ frequency; period = 1 ÷ frequency; c = 299,792,458 m/s. At the worked-example inputs the wavelength (m) is 3.
What does the wavelength and frequency result mean?
Turn a radio station or a Wi-Fi channel's frequency into the size of its wave. At the worked-example inputs the wavelength (m) is 3. It falls as frequency (mhz) increases.
How much does frequency (mhz) change the wavelength (m)?
Holding every other input at the worked-example value, moving frequency (mhz) from 80 to 120 moves the wavelength (m) from 2.5 to 3.7, a spread of 1.2.
What are the limits of this wavelength and frequency calculator?
These are textbook formulas for ideal conditions: no air resistance, no friction, gravity of 9.81 meters per second squared and gases that behave ideally. Real results differ, so treat them as first estimates and use the units the formulas expect (meters, kilograms, seconds). The tables on this page test frequency (mhz) only from 80 to 120; a value outside that range is not tabulated here.
If I double frequency (mhz) in the wavelength and frequency calculator, does the wavelength (m) double?
Doubling it from 100 to 200 takes the wavelength (m) from 3 to 1.5, which is 0.50 times the worked-example figure. So it falls instead of rising. Halving it to 50 gives 6.
Which inputs change the period (nanoseconds) in the wavelength and frequency calculator?
At the worked-example inputs it is 10. Frequency (mhz) takes it from 11.1 to 9.1.
Why does kinetic energy grow with the square of speed?
Energy of motion is half the mass times the speed squared, so doubling the speed quadruples it. A car at 60 mph carries four times the energy of the same car at 30, which is why stopping distances lengthen so fast.
What is the difference between mass and weight?
Mass is how much matter an object has, in kilograms. Weight is the force gravity puts on that mass, in newtons. The same mass weighs about a sixth as much on the Moon.
How does horsepower relate to torque?
Power is torque times rotational speed. Horsepower equals torque in pound-feet times RPM divided by 5,252, so at 5,252 RPM the two numbers are equal.
Sources and evidence
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