Wavelength Calculator — Frequency, Speed & Wavelength (λ = v/f)λ = v/f · f = v/λ · v = f×λ · Hz · MHz · GHz · nm · m · c
Use this free Wavelength Calculator to instantly solve any unknown variable in the fundamental wave equation: λ = v / f — where λ (lambda) is the wavelength in metres (m), nanometres (nm), or centimetres (cm), v is the wave propagation speed in m/s (defaulting to the speed of light c = 3 × 10⁸ m/s for electromagnetic waves), and f is the frequency in Hz, kHz, MHz, or GHz. Enter any two known wave parameters to automatically solve the third — computing: wavelength (λ = v / f) · frequency (f = v / λ) · wave speed (v = f × λ) — with automatic unit conversion across all standard wavelength and frequency units: nm · μm · mm · cm · m · km · Hz · kHz · MHz · GHz · THz.
The λ = v/f wavelength equation is foundational across all areas of wave physics and electromagnetic spectrum analysis: visible light wavelength & colour spectrum (380–700 nm) · radio wave & RF frequency-wavelength conversion · microwave, WiFi (2.4 GHz & 5 GHz) & mobile network (4G/5G) wavelength · sound wave & acoustic wavelength calculation · X-ray, UV & infrared wavelength analysis · antenna design & resonant frequency wavelength calculation. Trusted by A-Level, AP Physics, IB Physics, JEE, and NEET students, RF and telecommunications engineers, optics and photonics researchers, antenna designers, and physics educators for precise wave speed, frequency, and wavelength calculations across the full electromagnetic spectrum — from radio waves (km wavelength) to gamma rays (pm wavelength).
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Wavelength Calculator — Frequency, Wavelength, and Wave Speed for Any Wave
Wavelength, frequency, and wave speed are related by v = fλ. For electromagnetic waves in vacuum, v = c = 3 × 10⁸ m/s. A radio wave at 100 MHz has wavelength λ = 3 m; visible light at 550 nm has frequency f = 5.45 × 10¹⁴ Hz; X-rays at 0.1 nm have frequency 3 × 10¹⁸ Hz. The wavelength calculator solves for any of the three variables, covering the complete electromagnetic spectrum from radio waves through gamma rays and also mechanical waves (sound, seismic, water waves) with user-specified wave speeds.
Antenna design is directly governed by wavelength. A half-wave dipole antenna is physically half the wavelength of the frequency it is designed to receive — a 100 MHz FM dipole is 1.5 m long; a 2.4 GHz WiFi antenna is 6.25 cm long; a 433 MHz IoT antenna is 34.6 cm long. Antenna length must match the wavelength to achieve resonance and maximum energy transfer. The calculator converts between frequency and the physical antenna dimensions for common antenna types (dipole, monopole, Yagi element) used in radio communication design.
Sound wavelength determines architectural acoustics. The wavelength of 125 Hz (a bass frequency) in air is 2.72 m — roughly the width of a room, which creates standing waves and bass buildup at specific positions. The wavelength of 8 kHz is only 4.3 cm, which is why high frequencies are absorbed by relatively thin acoustic panels while bass requires thick treatment. The calculator applies the speed of sound in air (343 m/s at 20°C) and other media (water, steel, concrete) to translate octave band frequencies into the physical wavelengths that govern room mode analysis.