Wavelength to Color Converter
Every color has a position relative to the visible spectrum — some directly, most only approximately. Move the slider to see what a given wavelength looks like, or drop in any color to find its closest match on the spectrum.
Every color has a position relative to the visible spectrum — some directly, most only approximately. Move the slider to see what a given wavelength looks like, or drop in any color to find its closest match on the spectrum.
Visible light runs from about 380nm (violet) to 700nm (red). Drag the slider to preview the color at any point in that range, or jump to a real-world monochromatic source below.
Color → Wavelength converts the selected sRGB color to CIE xy chromaticity using the D65 reference white point. From there it calculates a dominant wavelength — the point where a ray from white through your color's chromaticity coordinate crosses the spectral locus, the curve traced by pure single wavelengths — along with a spectral purity: how far your color sits along that ray, from washed-out near white to fully spectral at the locus itself.
These values describe the color's chromaticity, not its physical composition. A dominant wavelength is the closest matching pure hue, not a claim that the color is made of light at one wavelength — most colors, including nearly everything you'd pick in a design tool, are mixtures of many wavelengths.
Purples and magentas fall on the far side of white from the spectral locus, on what colorimetry calls the line of purples — they have no direct position on the spectral arc. For those, the tool reports a complementary wavelength instead: the pure hue on the opposite side of the diagram that, mixed with white, produces the color you picked.
≈{{ reverseResult.wavelength.toFixed(1) }}nm dominant wavelength
{{ reverseResult.purity.toFixed(0) }}% spectral purity
No direct spectral match — complementary wavelength ≈{{ reverseResult.wavelength.toFixed(1) }}nm
{{ reverseResult.purity.toFixed(0) }}% purity · this color is a purple/magenta, outside the rainbow
No dominant hue
This color reads as gray or neutral — it has no meaningful hue direction.
Method Used
Color → Wavelength converts the selected sRGB color to CIE xy chromaticity using the D65 reference white point. From there it calculates a dominant wavelength — the point where a ray from white through your color's chromaticity coordinate crosses the spectral locus, the curve traced by pure single wavelengths — along with a spectral purity: how far your color sits along that ray, from washed-out near white to fully spectral at the locus itself.
These values describe the color's chromaticity, not its physical composition. A dominant wavelength is the closest matching pure hue, not a claim that the color is made of light at one wavelength — most colors, including nearly everything you'd pick in a design tool, are mixtures of many wavelengths.
Purples and magentas fall on the far side of white from the spectral locus, on what colorimetry calls the line of purples — they have no direct position on the spectral arc. For those, the tool reports a complementary wavelength instead: the pure hue on the opposite side of the diagram that, mixed with white, produces the color you picked.