0000FF (blue) — RGB, HSL, CMYK and Contrast

Q: What text colour should sit on 0000FF?

Black gives 2.44:1 and white gives 8.59:1, so white wins at 8.59:1. That clears the 4.5:1 AA threshold for normal text and the 7:1 AAA threshold as well.

Every value recomputed from the hex code · WCAG 2.1 contrast ratios

A blue at 50% lightness and 100% saturation, which puts it at 8.59:1 against white and 2.44:1 against black. The tables below give the notation conversions, the tints and shades that keep the hue intact, and the harmonies that pair with it.

0000FF

Notation conversions

Notation	Value
HEX	`0000FF`
RGB	rgb(0, 0, 255)
HSL	hsl(240, 100%, 50%)
CMYK	cmyk(100%, 100%, 0%, 0%)
Relative luminance	0.0722
Perceived brightness	11.4 / 100

R=0 G=0 B=255 · hue 240.0° · saturation 100.0% · lightness 50.0%

Contrast against pure white and pure black

Pair this colour with the two extremes to see which is the safer text partner. AA needs 4.5:1 for body text and 3:1 for large text; AAA raises that to 7:1 and 4.5:1.

Against	Hex	Ratio	AA text	AA large	AAA text
#FFFFFF	`white`	8.59:1	pass	pass	pass
#000000	`black`	2.44:1	fail	fail	fail

Tints and shades

Lightness moves in ten-point steps while hue and saturation stay fixed, which keeps the colour recognisable in a scale. The last column is the ratio against white text, useful for deciding where a scale stops working as a background.

Step	Hex	HSL	vs white text
shade -30	`#000066`	hsl(240, 100%, 20%)	17.62:1
shade -20	`#000099`	hsl(240, 100%, 30%)	14.38:1
shade -10	`#0000cc`	hsl(240, 100%, 40%)	11.22:1
tint +10	`#3333ff`	hsl(240, 100%, 60%)	6.87:1
tint +20	`#6666ff`	hsl(240, 100%, 70%)	4.28:1
tint +30	`#9999ff`	hsl(240, 100%, 80%)	2.51:1

Harmonies

Scheme	Hex
Complementary	`#ffff00`
Analogous −30	`#0080ff`
Analogous +30	`#8000ff`
Triadic −120	`#00ff00`
Triadic +120	`#ff0000`

Take the channels apart and the numbers hold together: 0, 0 and 255 average 85, the strongest channel is 255 and the weakest 0, and that span is what pushes saturation to 100.0% at hue 240.0° and lightness 50.0%. Luminance 0.0722 with perceived brightness 11.4 out of 100 is why the white ratio (8.59:1) and the black ratio (2.44:1) diverge by 6.15. Entry 40 of 69, it steps to #000066 at minus thirty and #9999ff at plus thirty.

Nearby colours

191970 midnightblue 3F51B5 Indigo 500 4682B4 steelblue 708090 slategray 2196F3 Blue 500 4169E1 royalblue

Frequently asked questions

What text colour should sit on 0000FF?
Black gives 2.44:1 and white gives 8.59:1, so white wins at 8.59:1. That clears the 4.5:1 AA threshold for normal text and the 7:1 AAA threshold as well.

Do the CMYK numbers match a print workflow?
They are the naive conversion from RGB, which assumes no ink limit, no colour profile and no black generation strategy. Real print work needs a profile-aware conversion; the values here are the ones the converter reports and are best used as a starting point for a designer rather than a press-ready separations file.

Convert any other colour, or test a pair against each other, in the ColrShift colour converter and contrast checker. The colour library groups every entry on this site by hue family.