FF0000 (red) — RGB, HSL, CMYK and Contrast

Q: What text colour should sit on FF0000?

Black gives 5.25:1 and white gives 4.00:1, so black wins at 5.25:1. That clears the 4.5:1 AA threshold for normal text, but not the 7:1 AAA threshold.

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

A red at 50% lightness and 100% saturation, which puts it at 4.00:1 against white and 5.25:1 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.

FF0000

Notation conversions

Notation	Value
HEX	`FF0000`
RGB	rgb(255, 0, 0)
HSL	hsl(0, 100%, 50%)
CMYK	cmyk(0%, 100%, 100%, 0%)
Relative luminance	0.2126
Perceived brightness	29.9 / 100

R=255 G=0 B=0 · hue 0.0° · 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`	4.00:1	fail	pass	fail
#000000	`black`	5.25:1	pass	pass	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	`#660000`	hsl(0, 100%, 20%)	13.42:1
shade -20	`#990000`	hsl(0, 100%, 30%)	8.92:1
shade -10	`#cc0000`	hsl(0, 100%, 40%)	5.89:1
tint +10	`#ff3333`	hsl(0, 100%, 60%)	3.64:1
tint +20	`#ff6666`	hsl(0, 100%, 70%)	2.86:1
tint +30	`#ff9999`	hsl(0, 100%, 80%)	2.05:1

Harmonies

Scheme	Hex
Complementary	`#00ffff`
Analogous −30	`#ff0080`
Analogous +30	`#ff8000`
Triadic −120	`#0000ff`
Triadic +120	`#00ff00`

Read back from the notation table, FF0000 is rgb(255, 0, 0), which normalises to hue 0.0° at 100.0% saturation and 50.0% lightness. Its relative luminance of 0.2126 is what produces the two ratios above: 4.00:1 against white and 5.25:1 against black, a gap of 1.25. Position 3 of 69 in the colour library, it darkens to #660000 thirty points lower on the lightness axis and lifts to #ff9999 thirty higher, while the complementary rotation lands on #00ffff.

Nearby colours

800000 maroon DC143C crimson FF5722 Deep Orange 500 F44336 Red 500 FF6347 tomato

Frequently asked questions

What text colour should sit on FF0000?
Black gives 5.25:1 and white gives 4.00:1, so black wins at 5.25:1. That clears the 4.5:1 AA threshold for normal text, but not the 7:1 AAA threshold.

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.