Color Converter
Convert between color formats and check accessibility.
Accessibility Check
WCAG 2.1 Level AA requires a contrast ratio of at least 4.5:1 for normal text.
#0FA89E
rgb(15, 168, 158)
hsl(176, 84%, 36%)
cmyk(91%, 0%, 6%, 34%)
hsv(176, 91%, 66%)
Unknown
How the colour models relate
HEX and RGB describe exactly the same thing: three eight-bit channels of red, green and blue, where HEX is simply the hexadecimal notation of the same 0–255 values, so #FF8000 and rgb(255, 128, 0) are identical colours. HSL and HSV re-express those channels in polar form as a hue angle from 0 to 360 degrees plus saturation and either lightness or value, which makes them far easier to reason about when building a palette: holding hue fixed and stepping lightness produces a coherent tint and shade ramp that is awkward to express in raw RGB. CMYK is a subtractive model used for print, where ink absorbs light rather than emitting it.
Why CMYK conversion is an approximation
The CMYK values shown here use the standard naive conversion, which assumes ideal inks and no colour management. Real printing depends on the press, the ink set, the paper stock and an ICC profile, and the printable gamut is smaller than the sRGB gamut a screen can display. Saturated cyans, oranges and greens that look correct on a monitor commonly shift when printed. Treat the CMYK output as a starting point for design work and always confirm critical brand colours against a profiled proof or a physical swatch book.
Contrast ratio and accessibility
The contrast checker follows the WCAG 2.1 definition, computing relative luminance for each colour after linearising the sRGB channels, then taking the ratio of the lighter to the darker luminance offset by 0.05. Ratios run from 1:1 for identical colours to 21:1 for black on white. WCAG level AA asks for at least 4.5:1 for body text and 3:1 for large text of 18 point or 14 point bold and above, while level AAA raises those thresholds to 7:1 and 4.5:1. User interface components and meaningful graphics need at least 3:1 against their background. Because the formula is luminance-based, two colours with similar hue but very different brightness can pass while two vivid hues of similar brightness fail, which is why contrast must be measured rather than judged by eye.