Wavelength to Color Calculator
Convert visible light wavelength in nm to color name, hex code, and frequency in THz.
Covers the full spectrum from violet (380 nm) to red (700 nm).
Light wavelength to visible color conversion maps the electromagnetic spectrum’s visible range (approximately 380–780 nanometers) to the colors perceived by the human eye. The relationship between wavelength and color is determined by physics, but the subjective experience of color also involves the eye’s cone cells.
Speed of light formula (connecting wavelength and frequency): c = λ × f
Therefore: Frequency (f) = c ÷ λ Wavelength (λ) = c ÷ f
Where:
- c = speed of light = 299,792,458 m/s (≈ 3 × 10⁸ m/s)
- λ (lambda) = wavelength in meters (or nanometers: 1 nm = 10⁻⁹ m)
- f = frequency in hertz (Hz)
Energy of a photon: E = h × f = h × c ÷ λ
Where:
- h = Planck’s constant = 6.626 × 10⁻³⁴ J·s
- Higher frequency (shorter wavelength) = more energetic photons
The visible spectrum (approximate wavelength ranges):
| Color | Wavelength (nm) | Frequency (THz) |
|---|---|---|
| Violet | 380–450 | 668–789 |
| Blue | 450–495 | 606–668 |
| Cyan | 495–520 | 577–606 |
| Green | 520–565 | 531–577 |
| Yellow | 565–590 | 508–531 |
| Orange | 590–625 | 480–508 |
| Red | 625–780 | 384–480 |
What each variable means:
- Nanometer (nm): one billionth of a meter; the standard unit for visible light wavelengths
- Terahertz (THz): the frequency unit; 1 THz = 10¹² Hz; visible light oscillates hundreds of trillions of times per second
- Beyond visible: UV light < 380nm (causes sunburn); infrared > 780nm (felt as heat)
- Perceived color vs. physical wavelength: color perception also depends on context, surrounding colors, and individual variation in cone cell sensitivity
Worked example: Laser pointer wavelength: 532 nm (common green laser).
- Frequency = (3 × 10⁸) ÷ (532 × 10⁻⁹) = 3 × 10⁸ ÷ 5.32 × 10⁻⁷ = 5.639 × 10¹⁴ Hz = 563.9 THz
- Color: Green (520–565 nm range): confirmed ✓
- Energy per photon = (6.626 × 10⁻³⁴) × (5.639 × 10¹⁴) = 3.737 × 10⁻¹⁹ joules per photon (2.33 eV)
The human eye is most sensitive to green light (~555 nm), which is why night vision equipment uses green displays and many safety signals use green color.