Visible Light Spectrum Calculator
Explore the complete visible light spectrum from 380 to 700 nm including wavelengths, frequencies, and photon energies of all colors. Interactive spectrum tool and color lookup calculator included.
Click or hover anywhere on the spectrum to explore wavelengths, colors, and properties
Click any row to explore that color in the calculator above
| Color | Wavelength Range (nm) | Frequency Range (THz) | Photon Energy (eV) | Example |
|---|
Extended Electromagnetic Spectrum Context
| Region | Wavelength Range | Frequency Range | Notes |
|---|---|---|---|
| Gamma rays | < 0.01 nm | > 30 EHz | Nuclear reactions |
| X-rays | 0.01–10 nm | 30 PHz–30 EHz | Medical imaging |
| Ultraviolet | 10–380 nm | 790 THz–30 PHz | Sunburn, sterilization |
| Visible light | 380–700 nm | 428–789 THz | Human vision |
| Infrared | 700 nm–1 mm | 300 GHz–428 THz | Heat, remote controls |
| Microwave | 1 mm–1 m | 300 MHz–300 GHz | WiFi, microwave ovens |
| Radio | > 1 m | < 300 MHz | Broadcasting |
What is the Visible Light Spectrum?
The visible light spectrum is the portion of the electromagnetic spectrum that can be detected by the human eye. It represents a small but crucial band of electromagnetic radiation, spanning wavelengths from approximately 380 nanometers (violet) to 700 nanometers (red).
Key characteristics of visible light:
- Wavelength range: 380 nm to 700 nm (3.8 × 10-7 m to 7.0 × 10-7 m)
- Frequency range: approximately 428 THz (red) to 789 THz (violet)
- Part of the electromagnetic spectrum: between ultraviolet (UV) and infrared (IR) radiation
- Travel speed: all electromagnetic radiation travels at c = 3 × 108 m/s in vacuum
Visible light is an example of electromagnetic radiation — transverse waves consisting of oscillating electric and magnetic fields perpendicular to each other and to the direction of propagation. Unlike sound waves, electromagnetic waves do not require a medium and can travel through the vacuum of space.
Defining Key Terms
Nanometer (nm): One billionth of a meter (1 nm = 10-9 m). The nanometer is the standard unit for measuring visible light wavelengths because the values fall in a convenient range (380–700 nm).
Wavelength (?): The distance between two consecutive wave crests (or troughs). For visible light, shorter wavelengths appear violet/blue, while longer wavelengths appear orange/red.
Frequency (f): The number of complete wave cycles that pass a point per second, measured in Hertz (Hz). Frequency and wavelength are inversely related by the equation f = c/?.
Photon energy (E): The energy carried by a single photon of light, calculated using Planck's equation E = hf, where h = 6.626 × 10-34 J·s is Planck's constant.
The relationship: For visible light, shorter wavelength = higher frequency = higher photon energy. This is why violet light (380 nm) has nearly twice the photon energy of red light (700 nm).
Colors of the Visible Spectrum — Wavelengths and Frequencies
The visible spectrum contains seven main color bands, each occupying a specific wavelength range. Here are the colors in order from longest to shortest wavelength:
Why Different Wavelengths Produce Different Colors
The human eye contains three types of cone cells (photoreceptors) sensitive to different wavelength ranges:
- L-cones (Long wavelength): peak sensitivity ~560 nm (yellow-green to red)
- M-cones (Medium wavelength): peak sensitivity ~530 nm (green)
- S-cones (Short wavelength): peak sensitivity ~420 nm (blue-violet)
Different wavelengths stimulate these cones in different ratios. The brain interprets these ratios as specific colors. For example, 700 nm light primarily stimulates L-cones, which the brain perceives as red.
Purple vs Violet: Violet (~380–450 nm) is a spectral color — it exists in the rainbow. Purple is a non-spectral color created by mixing red and blue light. True violet has the highest energy of any visible color; purple is perceived when both L-cones (red) and S-cones (blue) are stimulated simultaneously.
Wavelength of Visible Light — Range and Values
Here are the fundamental values that define the visible light spectrum:
How Wavelength and Frequency Relate
For all electromagnetic radiation, wavelength (?) and frequency (f) are inversely related by the speed of light:
f = c / ?
Example: Calculate frequency of green light (? = 550 nm)
- Convert wavelength to meters: ? = 550 nm = 550 × 10-9 m = 5.50 × 10-7 m
- Speed of light: c = 299,792,458 m/s
- Apply formula: f = c/? = 299,792,458 ÷ (5.50 × 10-7)
- Calculate: f = 5.45 × 1014 Hz
- Convert to THz: f = 545 THz
Answer: 545 THz — the frequency of green light at 550 nm
Midpoint Wavelength Reference Table
| Color | Wavelength (nm) | Frequency (THz) | Photon Energy (eV) |
|---|---|---|---|
| Violet | 415 nm | 723 THz | 2.99 eV |
| Blue | 472 nm | 635 THz | 2.63 eV |
| Cyan | 507 nm | 591 THz | 2.44 eV |
| Green | 542 nm | 553 THz | 2.29 eV |
| Yellow | 577 nm | 519 THz | 2.15 eV |
| Orange | 607 nm | 494 THz | 2.04 eV |
| Red | 662 nm | 453 THz | 1.87 eV |
What Two Properties of a Light Wave Determine Color?
The color we perceive from light is determined by two fundamental wave properties:
1. Wavelength (or Frequency) — Determines HUE
Wavelength is the primary property that determines which color we see. Each wavelength in the visible spectrum (380–700 nm) corresponds to a specific hue:
- 380–450 nm ? Violet
- 450–495 nm ? Blue
- 495–520 nm ? Cyan
- 520–565 nm ? Green
- 565–590 nm ? Yellow
- 590–625 nm ? Orange
- 625–700 nm ? Red
Because wavelength and frequency are inversely related (f = c/?), you can also say frequency determines hue. Higher frequency (shorter wavelength) = violet/blue colors. Lower frequency (longer wavelength) = orange/red colors.
2. Intensity (Amplitude) — Determines BRIGHTNESS
Intensity (or amplitude) determines how bright the color appears. Intensity is the amount of energy delivered per unit area per unit time. For light waves:
- Higher amplitude = more photons per second = brighter light
- Lower amplitude = fewer photons per second = dimmer light
A 550 nm light wave at high intensity appears as bright green. The same 550 nm wavelength at low intensity appears as dim green. The hue stays green (determined by wavelength), but brightness changes (determined by amplitude).
Bonus: Saturation (Purity)
While not a fundamental wave property, saturation describes how pure a color appears:
- Pure (saturated) colors: single wavelength light (e.g., 550 nm laser = pure green)
- Desaturated colors: mixture of wavelengths (e.g., white light = all visible wavelengths mixed)
Spectral vs Non-Spectral Colors
Spectral colors appear in the rainbow and correspond to a single wavelength: red, orange, yellow, green, cyan, blue, violet.
Non-spectral colors do not appear in the rainbow and cannot be produced by a single wavelength:
- Magenta/Purple: perceived when both red and blue cones are stimulated (no single wavelength does this)
- Pink: desaturated red (red light mixed with white light)
- Brown: desaturated orange (orange light at low brightness)
- White/Gray/Black: achromatic — no dominant wavelength
Where is Visible Light Located on the Electromagnetic Spectrum?
Visible light occupies a tiny fraction of the full electromagnetic spectrum, sandwiched between ultraviolet (UV) radiation and infrared (IR) radiation.
Position and Context
- Shorter wavelengths than visible (higher energy):
- Ultraviolet (UV): 10–380 nm — causes sunburn, used for sterilization
- X-rays: 0.01–10 nm — medical imaging, airport security
- Gamma rays: < 0.01 nm — nuclear reactions, cancer treatment
- Longer wavelengths than visible (lower energy):
- Infrared (IR): 700 nm–1 mm — heat radiation, thermal imaging
- Microwave: 1 mm–1 m — WiFi, microwave ovens, radar
- Radio: > 1 m — broadcasting, mobile communication
Why Humans Evolved to See This Specific Range
There are three reasons the human eye is sensitive to 380–700 nm wavelengths:
- Solar radiation peak: The Sun emits peak radiation at ~500 nm (green-yellow), right in the middle of the visible spectrum. Evolution optimized our eyes to detect the most abundant wavelengths.
- Atmospheric window: Earth's atmosphere is transparent to visible light but absorbs most UV and IR. Visible light reaches the surface efficiently.
- Water transparency: Visible light penetrates water well (important for early aquatic life). UV is absorbed quickly; IR is absorbed even faster.
Many animals see different ranges. Bees see UV light (300–650 nm) but not red. Snakes see infrared. The "visible" spectrum is visible to humans — not a universal property of light.
Wavelengths of Each Color in the Visible Spectrum
This section answers the most common student questions about specific color wavelengths.
What wavelength is violet?
Violet light: 380–450 nm (typical: ~415 nm)
- Frequency: 666–789 THz (typical: ~723 THz)
- Photon energy: 2.76–3.26 eV (typical: ~2.99 eV)
- Shortest visible wavelength — highest frequency and highest energy
- Often confused with purple (purple is a mixture, not in the spectrum)
What wavelength is blue?
Blue light: 450–495 nm (typical: ~472 nm)
- Frequency: 606–666 THz (typical: ~635 THz)
- Photon energy: 2.50–2.76 eV (typical: ~2.63 eV)
- Responsible for the color of the sky (Rayleigh scattering favors shorter wavelengths)
- Second shortest visible wavelength — second highest energy
What wavelength is cyan?
Cyan light: 495–520 nm (typical: ~507 nm)
- Frequency: 577–606 THz (typical: ~591 THz)
- Photon energy: 2.38–2.50 eV (typical: ~2.44 eV)
- Between blue and green
- One of the primary colors in the CMYK color model (printing)
What wavelength is green?
Green light: 520–565 nm (typical: ~542 nm)
- Frequency: 531–577 THz (typical: ~553 THz)
- Photon energy: 2.19–2.38 eV (typical: ~2.29 eV)
- Peak sensitivity of human vision is at ~555 nm (yellow-green)
- Dominant color in nature due to chlorophyll absorption spectrum
What wavelength is yellow?
Yellow light: 565–590 nm (typical: ~577 nm)
- Frequency: 508–531 THz (typical: ~519 THz)
- Photon energy: 2.10–2.19 eV (typical: ~2.15 eV)
- Sunlight appears yellow-white due to the solar emission peak at ~500 nm
- Sodium vapor lamps emit at 589 nm (yellow-orange)
What wavelength is orange?
Orange light: 590–625 nm (typical: ~607 nm)
- Frequency: 480–508 THz (typical: ~494 THz)
- Photon energy: 1.98–2.10 eV (typical: ~2.04 eV)
- Between yellow and red
- Named after the fruit (the color name came after the fruit)
What wavelength is red?
Red light: 625–700 nm (typical: ~662 nm)
- Frequency: 428–480 THz (typical: ~453 THz)
- Photon energy: 1.77–1.98 eV (typical: ~1.87 eV)
- Longest visible wavelength — lowest frequency and lowest energy
- Used in stop lights because it scatters least through fog and travels farthest
Which color has the longest wavelength?
Red light has the longest wavelength in the visible spectrum (625–700 nm). The boundary is not sharp — wavelengths beyond ~700 nm transition into near-infrared, which the human eye cannot detect.
Which color has the shortest wavelength and highest frequency?
Violet light has the shortest wavelength (380–450 nm) and highest frequency (666–789 THz) in the visible spectrum. It also has the highest photon energy (~3 eV). Below ~380 nm, light transitions into ultraviolet (UV), which is invisible to humans but can damage skin and eyes.
Worked Examples
1. How to calculate the frequency of green light (? = 550 nm)
Solution:
- Given: ? = 550 nm
- Convert to meters: ? = 550 × 10-9 m = 5.50 × 10-7 m
- Speed of light: c = 299,792,458 m/s
- Formula: f = c/?
- Calculate: f = 299,792,458 ÷ 5.50×10-7 = 5.451 × 1014 Hz
- Convert to THz: f = 545.1 THz
Answer: 5.45 × 1014 Hz = 545 THz
2. How to find the photon energy of blue light (? = 470 nm)
Solution:
- Given: ? = 470 nm = 4.70 × 10-7 m
- First find frequency: f = c/? = 299,792,458 ÷ 4.70×10-7 = 6.378 × 1014 Hz
- Planck's constant: h = 6.626 × 10-34 J·s
- Calculate energy in joules: E = hf = 6.626×10-34 × 6.378×1014 = 4.226 × 10-19 J
- Convert to eV: E = 4.226×10-19 ÷ 1.602×10-19 = 2.64 eV
Answer: E = 4.23 × 10-19 J = 2.64 eV
3. What is the wavelength of visible light that appears red?
Answer: Red light occupies the wavelength range 625–700 nm. The typical midpoint is ~662 nm. Light at 625 nm appears orange-red, while light at 700 nm appears deep red at the edge of visibility.
4. Which color of visible light has the highest frequency?
Answer: Violet light has the highest frequency in the visible spectrum, ranging from 666 THz to 789 THz. At the violet boundary (~380 nm), frequency reaches ~789 THz. Higher frequencies fall into the ultraviolet (UV) range and are not visible to the human eye.
5. Which color has the longest wavelength in the visible spectrum?
Answer: Red light has the longest wavelength in the visible spectrum, ranging from 625 nm to 700 nm. Wavelengths longer than ~700 nm fall into the infrared (IR) range and are felt as heat but not seen as light.
6. How to convert visible light wavelength from nm to meters
Method: Multiply the wavelength in nanometers by 10-9
Example: Convert 550 nm to meters
- ? = 550 nm
- ? = 550 × 10-9 m
- ? = 5.50 × 10-7 m = 0.00000055 m
Quick rule: nm to m = move decimal point 9 places left
7. What is the frequency range of visible light?
Answer: The frequency range of visible light is approximately 428 THz to 789 THz (or 4.28×1014 Hz to 7.89×1014 Hz). Red light is at the low end (~428 THz) and violet light is at the high end (~789 THz).
8. How to find the frequency of violet light (? = 400 nm)
Solution:
- Given: ? = 400 nm = 4.00 × 10-7 m
- Formula: f = c/?
- Calculate: f = 299,792,458 ÷ 4.00×10-7 = 7.495 × 1014 Hz
- Convert to THz: f = 749.5 THz
Answer: 7.49 × 1014 Hz = 750 THz (approximately)
9. Where does visible light fall on the electromagnetic spectrum?
Answer: Visible light occupies the wavelength range 380–700 nm on the electromagnetic spectrum, positioned between:
- Ultraviolet (UV): 10–380 nm (higher energy, shorter wavelength)
- Infrared (IR): 700 nm–1 mm (lower energy, longer wavelength)
Visible light represents less than 1% of the full electromagnetic spectrum, which ranges from gamma rays (<0.01 nm) to radio waves (>1 m).
10. How to calculate photon energy from wavelength in nm
Method:
- Convert wavelength from nm to m: ?(m) = ?(nm) × 10-9
- Calculate frequency: f = c/? where c = 299,792,458 m/s
- Calculate energy in joules: E = hf where h = 6.626×10-34 J·s
- Convert to eV: E(eV) = E(J) ÷ 1.602×10-19
Example: ? = 500 nm
- ? = 500 × 10-9 = 5×10-7 m
- f = 299,792,458 ÷ 5×10-7 = 5.996×1014 Hz
- E = 6.626×10-34 × 5.996×1014 = 3.972×10-19 J
- E = 3.972×10-19 ÷ 1.602×10-19 = 2.48 eV
Answer: 2.48 eV
Frequently Asked Questions
Related Calculators
| Range | 380–700 nm |
| Frequency | 428–789 THz |
| Speed | 3×108 m/s |
| Longest ? | Red (~700 nm) |
| Shortest ? | Violet (~380 nm) |
| Peak Eye | ~555 nm (green) |
| Color | ? (nm) |
|---|---|
| Violet | 380–450 |
| Blue | 450–495 |
| Cyan | 495–520 |
| Green | 520–565 |
| Yellow | 565–590 |
| Orange | 590–625 |
| Red | 625–700 |
| f = c/? | Frequency |
| E = hf | Photon energy |
| ? = 2pf | Angular freq |