What is the formula for Wavelength?

The Wavelength formula is λ = c / f, where λ—Wavelength in meters (m); f—Frequency in hertz (Hz); c—Speed of light ≈ 3 × 10⁸ m/s.

What does λ mean in the Wavelength formula?

λ is Wavelength in meters (m).

Wavelength

Q: How do you calculate Wavelength?

Use the formula λ = c / f. The wavelength of an electromagnetic wave is inversely proportional to its frequency, with the speed of light (approximately 3 × 10^8 m/s in vacuum) as the constant of proportionality. Enter the values you know in the calculator above and it solves for the remaining variable.

λ = c / f

Calculator

Wavelength

Frequency

Result

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Formula

λ = c / f

Description

The wavelength of an electromagnetic wave is inversely proportional to its frequency, with the speed of light (approximately 3 × 10^8 m/s in vacuum) as the constant of proportionality. This relationship is fundamental to antenna design, where antenna dimensions are typically fractions or multiples of the wavelength. For example, a quarter-wave antenna for 2.4 GHz WiFi is about 3.1 cm long. Wavelength also determines how signals interact with objects: signals with wavelengths much larger than an obstacle diffract around it, while shorter wavelengths are reflected or absorbed.

Variables

λ — Wavelength in meters (m)
f — Frequency in hertz (Hz)
c — Speed of light ≈ 3 × 10⁸ m/s

Practical Notes

In transmission lines and PCB traces, the effective wavelength is shorter than free space due to the dielectric constant: λ_eff = λ / √εr. At 1 GHz, the free-space wavelength is 30 cm. When trace lengths approach λ/10, transmission line effects become significant and impedance matching is required.

Related Concepts

All Signal & RF formulas →

Wavelength Free Space Path Loss Signal-to-Noise Ratio Nyquist Sampling Rate Link Budget Antenna Gain Skin Depth Friis Noise Figure (3-stage)

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