Frequency to Wavelength Converter – c = λf Calculator

This calculator uses c = 299,792,458 meters per second, which is the exact value defined by the International System of Units (SI). This is the speed of electromagnetic waves in a vacuum. In other media like air, water, or glass, the speed of light is slower, and the wavelength changes accordingly while the frequency remains constant.

Frequency units: Hz, kHz (10³ Hz), MHz (10⁶ Hz), GHz (10⁹ Hz), and THz (10¹² Hz).
Wavelength units: meters (m), centimeters (cm), millimeters (mm), micrometers (μm), nanometers (nm), and ångströms (Å, where 1 Å = 10⁻¹⁰ m). The calculator automatically handles all unit conversions, so you can mix and match any frequency unit with any wavelength unit.

This tool automatically classifies your result into one of these categories based on wavelength:
• Gamma rays: λ < 0.01 nm (f > 30 EHz)
• X-rays: 0.01 nm – 10 nm (30 PHz – 30 EHz)
• Ultraviolet: 10 nm – 380 nm (790 THz – 30 PHz)
• Visible light: 380 nm – 700 nm (430 THz – 790 THz)
• Infrared: 700 nm – 1 mm (300 GHz – 430 THz)
• Microwaves: 1 mm – 1 m (300 MHz – 300 GHz)
• Radio waves: λ > 1 m (f < 300 MHz)

When light travels from one medium to another, its speed changes, but its frequency remains constant because frequency is determined by the source. Since c = λf, if c decreases (e.g., in water or glass), the wavelength λ must decrease proportionally to keep f unchanged. This calculator uses the vacuum speed of light; for other media, multiply the wavelength by the medium's refractive index.

Yes! The calculator uses scientific notation and supports a wide range of values. You can enter numbers like 3e8 (3 × 10⁸) directly into the input fields. It handles frequencies from sub-hertz radio waves up to gamma-ray frequencies exceeding 10²⁰ Hz, automatically formatting results with appropriate precision.

• Wi-Fi 2.4 GHz → wavelength ≈ 12.5 cm
• Wi-Fi 5 GHz → wavelength ≈ 6 cm
• FM Radio 100 MHz → wavelength ≈ 3 m
• Green visible light 550 nm → frequency ≈ 545 THz
• Bluetooth 2.45 GHz → wavelength ≈ 12.2 cm
• 5G mmWave 28 GHz → wavelength ≈ 1.07 cm
Use the preset buttons above to explore these values instantly.