The electromagnetic spectrum spans from radio waves to gamma rays, covering over 25 octaves of frequency. Use the interactive chart below to explore each region, convert wavelength to frequency and energy, and discover real-world applications of each EM band.
Interactive EM Spectrum
Click or drag to explore. Click a region label to see details.
Wavelength / Frequency / Energy Converter
How to Use the EM Spectrum Reference
This reference combines an interactive spectrum visualization with a tri-unit converter covering all seven EM regions. It's useful for physics coursework, understanding how devices work, and converting between wavelength, frequency, and photon energy.
Reading the Spectrum Chart
The horizontal bar shows all EM regions on a logarithmic frequency scale. Move your cursor over the bar to read the wavelength, frequency, and photon energy at that point. The region changes color to indicate your position. Click any region to open the detail panel with wavelength ranges and real-world applications.
Converting Wavelength to Frequency
Use the converter below the spectrum. Enter a wavelength of 500nm and the tool calculates frequency as c/λ = (3×10⁸ m/s) / (500×10⁻⁹ m) = 6×10¹⁴ Hz (600 THz) — green visible light. Photon energy follows as E = hf = (6.626×10⁻³⁴ J·s) × (6×10¹⁴ Hz) = 3.97×10⁻¹⁹ J or 2.48 eV.
Understanding the Regions
Radio waves (wavelengths of meters to kilometers) carry AM/FM broadcasts, TV signals, and mobile communications. Microwaves (1mm–1m) power WiFi, Bluetooth, radar, and microwave ovens. Infrared (700nm–1mm) is felt as heat and used in remote controls and night-vision cameras. Visible light (400–700nm) is what human eyes detect — from violet (400nm) to red (700nm). UV (10–400nm) causes sunburn and drives photosynthesis. X-rays (0.01–10nm) penetrate soft tissue and create medical images. Gamma rays (<0.01nm) are emitted by nuclear reactions and used in cancer radiotherapy.
The E = hf Relationship
Photon energy increases linearly with frequency: E = hf, where h = 6.626×10⁻³⁴ J·s. This is why UV and gamma rays are ionizing (they carry enough energy per photon to break chemical bonds) while radio waves are not. The energy difference between a radio photon (10⁻²⁷ J) and a gamma photon (10⁻¹¹ J) is 16 orders of magnitude.
FAQ
What is the electromagnetic spectrum?
The electromagnetic spectrum is the complete range of electromagnetic radiation, ordered by wavelength or frequency. It spans from radio waves (wavelengths of kilometers) to gamma rays (wavelengths smaller than an atom). All EM radiation travels at the speed of light (3×10⁸ m/s) in vacuum.
What are the regions of the EM spectrum?
From lowest to highest frequency: Radio (>1mm), Microwave (1mm–1m), Infrared (700nm–1mm), Visible Light (400–700nm), Ultraviolet (10–400nm), X-ray (0.01–10nm), and Gamma ray (<0.01nm). The boundaries between regions are approximate and overlap in some classification systems.
How are wavelength and frequency related?
They are inversely related: c = λ × f, where c = 3×10⁸ m/s is the speed of light. A wavelength of 500nm (green light) corresponds to a frequency of 6×10¹⁴ Hz (600 THz). Lower wavelength means higher frequency and higher photon energy.
What is photon energy?
Photon energy is E = h × f = hc/λ, where h = 6.626×10⁻³⁴ J·s is Planck's constant. For visible light at 500nm, E ≈ 3.97×10⁻¹⁹ J or about 2.48 eV. Gamma rays can have energies above 1 MeV (millions of electron volts).
Is this tool free?
Yes, completely free with no signup required. All calculations run in your browser.
Why is visible light such a small part of the spectrum?
Visible light (400–700nm) covers less than one octave of frequency, while the entire EM spectrum spans more than 25 octaves. Human eyes evolved to detect the peak wavelengths emitted by the Sun, which has a surface temperature of ~5,778K producing maximum output in the visible range.
What everyday devices use different EM regions?
Radio (AM/FM broadcasting, TVs), Microwave (WiFi, Bluetooth, microwave ovens, radar), Infrared (TV remotes, night-vision cameras, heat cameras), Visible (cameras, displays, fiber optics), UV (tanning beds, sterilization lights), X-ray (medical imaging, airport security), Gamma (cancer radiation therapy, PET scans).