What color is a wavelength of 500 nm?

In this declared display model, a vacuum-equivalent wavelength of 500 nm at 100% display brightness gives RGB(0, 255, 146), or #00ff92. Its frequency in vacuum is 599584916000000 Hz and its photon energy is about 2.47968397 eV. An RGB display does not reproduce a measured monochromatic spectral color.

How are wavelength, frequency and photon energy related?

Frequency is propagation speed divided by wavelength: f = v / λ. Photon energy is E = h × f, using h = 6.62607015 × 10^-34 J·s. The eV conversion uses 1 eV = 1.602176634 × 10^-19 J. Vacuum speed is exactly 299792458 m/s; calculations use floating-point arithmetic.

Does changing units change the physical value?

No. Switching between wavelength units, frequency units, or the two input quantities converts the current valid value. For example, 500 nm is 0.5 µm or 0.0000005 m. Correct an invalid value before changing units; the tool keeps your input and explains the error.

What happens when I enter a custom propagation speed?

Applying a new speed holds the current frequency fixed and recalculates wavelength. The result labels that wavelength as in-medium. The color swatch uses the vacuum-equivalent wavelength c / f. For example, speed 149896229 m/s and wavelength 250 nm have the same frequency and approximate display color as 500 nm in vacuum.

Which wavelengths have a color swatch?

The model covers vacuum-equivalent wavelengths from 380 through 780 nm, including both endpoints. Outside that range the swatch is unavailable. The piecewise RGB ramps include attenuation at the visible edges and gamma 0.8. Display brightness scales only the approximate RGB swatch; it does not change frequency or photon energy.

What is included in the SVG chart and copied values?

Both include the input quantity, units, propagation speed assumption, wavelength, frequency, photon energy and color-model context. The SVG adds an original two-cycle schematic with a labelled wavelength. The wave amplitude is illustrative and has no physical unit; neither the chart nor the brightness control represents optical power.

Are my values sent to a server?

The conversion and SVG generation run in your browser. Valid settings are remembered on this device when browser storage is available. Restored values need an explicit Update spectrum action before a new result is prepared. Use the page's Start over control to forget the saved settings.

Which visible color has the longest or shortest wavelength?

Red lies at the long-wavelength end of visible light, while violet lies at the short-wavelength end. At the same propagation speed, shorter wavelength means higher frequency and higher photon energy. The reference chart orders the colors from violet to red; its 380 to 780 nm limits belong to this display model rather than a sharp universal boundary of human vision. At a fixed speed, one color cannot have both the highest frequency and the longest wavelength; those orderings are opposite.

Can I convert a color back to one wavelength?

Choose a named sample such as Blue at 460 nm, Green at 540 nm or Red at 700 nm to load a representative vacuum wavelength. Press Update spectrum to calculate its frequency, energy and approximate RGB. A color name spans many wavelengths, and an arbitrary RGB value can describe mixtures, so this tool does not infer a unique physical wavelength from RGB or an object photograph.

How does the wavelength wheel differ from a color wheel?

This wheel curves the same increasing wavelength sequence into an open arc, with labelled violet and red endpoints. The gap prevents red and violet from appearing adjacent in wavelength. It is a spectral display reference, not a pigment mixing, complementary-color or absorption wheel. The color sample buttons work with a keyboard or touch.

Do white, black, brown, pink or purple have one wavelength?

These names do not generally identify a single monochromatic wavelength. White can contain a mixture of visible wavelengths; black describes little or no visible light. Brown, pink and purple commonly describe mixtures rather than one spectral band. A violet spectral sample is provided, but it is not an inverse conversion for every purple RGB value.

Does the strongest color mean the highest photon energy?

Photon energy increases with frequency and decreases with wavelength, so the violet end has higher energy per photon than the red end. Optical power also depends on how many photons arrive per second. This converter calculates energy per photon; it does not compare beam strength, exposure or equipment safety.

How do wavelength and mixtures affect the color we see?

Our eyes respond differently to different visible wavelengths. A monochromatic sample has one wavelength, while ordinary light can mix many wavelengths and still appear as one color. The same perceived hue can arise from different mixtures, so this RGB approximation cannot measure a spectrum or recover it from a color name.

Spectrum Explorer

Enter a wavelength or frequency to calculate photon energy and an approximate RGB color. Use the visible spectrum reference or choose a named color sample, then copy the values or download a schematic SVG wave chart.

Wave inputsVacuum currently applied

Approximate visible swatchModel range 380–780 nm

Follow one wave
through the spectrum.

Enter a wavelength or frequency, then update the spectrum. Your values, approximate color and labelled wave appear here.

Awaiting conversion

500 nm is ready as an example. Update spectrum to prepare your result.

Visible spectrum and wavelength wheel

Violet is at the short-wavelength end of visible light; red is at the long-wavelength end. Frequency and photon energy increase toward violet. This display model spans 380 to 780 nm; color names and visible limits have gradual boundaries.

380 nm580 nm780 nm

Choose a named color sample

The wheel bends the same wavelength sequence into an open arc; it is not a pigment or absorption wheel. Named samples are examples, not one exact wavelength for every object of that color. Select a sample, then press Update spectrum. The downloadable SVG contains the calculated wave and values.

Worked examples

How the display-color model works

The model uses RGB ramps over 380–440, 440–490, 490–510, 510–580, 580–645 and 645–780 nm. Edge attenuation rises from 0.3 at 380 nm to 1 at 420 nm, and falls from 1 at 700 nm to 0.3 at 780 nm. Each channel is rounded from 255 × (ramp × attenuation × brightness)⁰·⁸. The SVG and copied report preserve the model context.

Photon energy uses E = h × f with h = 6.62607015 × 10⁻³⁴ J·s. One eV is 1.602176634 × 10⁻¹⁹ J. Values are calculated with floating-point arithmetic; displayed summaries round to ten significant figures.

Accuracy. RGB is a display approximation, not a measured spectral color. Vacuum c=299792458m/s; no laser exposure, equipment safety or photometric claims.

Common questions

What color is a wavelength of 500 nm?: In this declared display model, a vacuum-equivalent wavelength of 500 nm at 100% display brightness gives RGB(0, 255, 146), or #00ff92. Its frequency in vacuum is 599584916000000 Hz and its photon energy is about 2.47968397 eV. An RGB display does not reproduce a measured monochromatic spectral color.
How are wavelength, frequency and photon energy related?: Frequency is propagation speed divided by wavelength: f = v / λ. Photon energy is E = h × f, using h = 6.62607015 × 10^-34 J·s. The eV conversion uses 1 eV = 1.602176634 × 10^-19 J. Vacuum speed is exactly 299792458 m/s; calculations use floating-point arithmetic.
Does changing units change the physical value?: No. Switching between wavelength units, frequency units, or the two input quantities converts the current valid value. For example, 500 nm is 0.5 µm or 0.0000005 m. Correct an invalid value before changing units; the tool keeps your input and explains the error.
What happens when I enter a custom propagation speed?: Applying a new speed holds the current frequency fixed and recalculates wavelength. The result labels that wavelength as in-medium. The color swatch uses the vacuum-equivalent wavelength c / f. For example, speed 149896229 m/s and wavelength 250 nm have the same frequency and approximate display color as 500 nm in vacuum.
Which wavelengths have a color swatch?: The model covers vacuum-equivalent wavelengths from 380 through 780 nm, including both endpoints. Outside that range the swatch is unavailable. The piecewise RGB ramps include attenuation at the visible edges and gamma 0.8. Display brightness scales only the approximate RGB swatch; it does not change frequency or photon energy.
What is included in the SVG chart and copied values?: Both include the input quantity, units, propagation speed assumption, wavelength, frequency, photon energy and color-model context. The SVG adds an original two-cycle schematic with a labelled wavelength. The wave amplitude is illustrative and has no physical unit; neither the chart nor the brightness control represents optical power.
Are my values sent to a server?: The conversion and SVG generation run in your browser. Valid settings are remembered on this device when browser storage is available. Restored values need an explicit Update spectrum action before a new result is prepared. Use the page's Start over control to forget the saved settings.
Which visible color has the longest or shortest wavelength?: Red lies at the long-wavelength end of visible light, while violet lies at the short-wavelength end. At the same propagation speed, shorter wavelength means higher frequency and higher photon energy. The reference chart orders the colors from violet to red; its 380 to 780 nm limits belong to this display model rather than a sharp universal boundary of human vision. At a fixed speed, one color cannot have both the highest frequency and the longest wavelength; those orderings are opposite.
Can I convert a color back to one wavelength?: Choose a named sample such as Blue at 460 nm, Green at 540 nm or Red at 700 nm to load a representative vacuum wavelength. Press Update spectrum to calculate its frequency, energy and approximate RGB. A color name spans many wavelengths, and an arbitrary RGB value can describe mixtures, so this tool does not infer a unique physical wavelength from RGB or an object photograph.
How does the wavelength wheel differ from a color wheel?: This wheel curves the same increasing wavelength sequence into an open arc, with labelled violet and red endpoints. The gap prevents red and violet from appearing adjacent in wavelength. It is a spectral display reference, not a pigment mixing, complementary-color or absorption wheel. The color sample buttons work with a keyboard or touch.
Do white, black, brown, pink or purple have one wavelength?: These names do not generally identify a single monochromatic wavelength. White can contain a mixture of visible wavelengths; black describes little or no visible light. Brown, pink and purple commonly describe mixtures rather than one spectral band. A violet spectral sample is provided, but it is not an inverse conversion for every purple RGB value.
Does the strongest color mean the highest photon energy?: Photon energy increases with frequency and decreases with wavelength, so the violet end has higher energy per photon than the red end. Optical power also depends on how many photons arrive per second. This converter calculates energy per photon; it does not compare beam strength, exposure or equipment safety.
How do wavelength and mixtures affect the color we see?: Our eyes respond differently to different visible wavelengths. A monochromatic sample has one wavelength, while ordinary light can mix many wavelengths and still appear as one color. The same perceived hue can arise from different mixtures, so this RGB approximation cannot measure a spectrum or recover it from a color name.

RGB is a display approximation, not a measured spectral color. Vacuum c=299792458m/s; no laser exposure, equipment safety or photometric claims.