#A51F18 Color

#A51F18 is rgb(165, 31, 24) in RGB, hsl(3, 75%, 37%) in HSL, and about cmyk(0%, 81%, 85%, 35%) in CMYK. It has no registered color name of its own — the closest is Spartan Crimson (#9E1316), very hard to tell apart at ΔE 3.12. White text is the more readable choice on this background.

#A51F18

HEX#A51F18

RGBrgb(165, 31, 24)

HSLhsl(3, 75%, 37%)

HSVhsv(3, 85%, 65%)

CMYKcmyk(0%, 81%, 85%, 35%)

OKLCHoklch(46.9% 0.171 28.8)

LABlab(36.76% 53.31 40.71)

LCHlch(36.76% 67.07 37.37)

What #A51F18 Is Called

Most hex codes have no name: there are 16.7 million of them and a few thousand registered names. These are the named colors nearest to #A51F18, ordered by CIE76 distance in CIELAB. Anything under about ΔE 2 is a difference most people cannot see.

Spartan Crimson#9E1316ΔE 3.12 Fire Brick#B22222ΔE 4.75 Upsdell Red#AE2029ΔE 7.69 OU Crimson Red#990000ΔE 7.96 Rufous#A81C07ΔE 8.05 Chinese Red#AA381EΔE 8.05

Browse the full index of named colors A-Z or every red in the library.

#A51F18 Channel Values

How #A51F18 breaks down in each color model. Hue is measured in degrees around the color wheel; saturation, lightness, and the CMYK inks are percentages.

Model	Channels	Notes
RGB	R 165 · G 31 · B 24	8-bit channels as sent to the display
HSL	H 3° · S 75% · L 37%	Easiest model for building lighter and darker variants
HSV	H 3° · S 85% · V 65%	Matches the picker in most design tools
CMYK	C 0% · M 81% · Y 85% · K 35%	Approximate ink mix; confirm with an ICC profile before printing
Luminance	7.48:1 vs white · 2.81:1 vs black	WCAG 2.2 relative-luminance contrast ratios

Text Contrast & Accessibility

WCAG 2.2 contrast ratios for text on a #A51F18 background. AA requires 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Contrast is one check, not a full accessibility review.

TextWhite text7.48:1AA normal AA large AAA normal

Fails AABlack text2.81:1AA normal AA large AAA normal

Need a specific ratio against another background? Open #A51F18 in the contrast checker.

Colors That Go With #A51F18

Pairings derived from color-wheel relationships. The complementary color sits opposite #A51F18; analogous colors sit beside it; triadic and split-complementary sets spread evenly around the wheel. Select any swatch for its own breakdown.

Base

Complementary

Analogous

Analogous

Triadic

Triadic

Split comp.

Split comp.

Tints & Shades of #A51F18

Lighter tints and darker shades built by moving the lightness channel while holding hue and saturation, which is what you want for hover states, backgrounds, and text variants.

Tints

Shades

Want a full 50-950 ramp with semantic roles? Generate design tokens from #A51F18.

How #A51F18 Looks with Color Vision Deficiency

Simulated with the Viénot, Brettel & Mollon LMS projection model. Anomalous types are rendered as partial versions of the matching dichromacy, which is an approximation rather than a per-person clinical model.

Typical#A51F18

Protanopia#4E4E15

Protanomaly#7A4016

Deuteranopia#666600

Deuteranomaly#84530A

Tritanopia#A51E1E

Tritanomaly#A51F1C

Achromatopsia#555555

Test a full palette in the color blindness simulator.

Using #A51F18 in Code

Copy-ready declarations for the places this color usually ends up.

CSS custom property--color-a51f18: #A51F18;

CSS backgroundbackground-color: #A51F18;

Tailwind configcolors: { 'color-a51f18': '#A51F18' }

SwiftUIColor(red: 0.647, green: 0.122, blue: 0.094)

Android XML<color name="color_a51f18">#A51F18</color>

SVG fillfill="#A51F18"

More Red Colors

#A51F18 sits in the red family. These are its neighbours across that family's full range, each with its own breakdown.

1f0000 fffafa 1f0005 fff5f5 1f0008 fff1f2 240000 fff1f0 240909 fff0f2 270707 ffedeb 4e0707 710f04 940000 a81c07 c0362c cdacac e30022 ee204d fa8072 ff1818 ff6467 ffb7c5

#A51F18 Frequently Asked Questions

What color is #A51F18?

#A51F18 is a dark red — rgb(165, 31, 24) in RGB and hsl(3, 75%, 37%) in HSL. It carries no registered color name of its own; the closest named color is Spartan Crimson (#9E1316), which is very hard to tell apart at a CIE76 distance of 3.12.

What is the RGB value of #A51F18?

#A51F18 is rgb(165, 31, 24) — red 165, green 31, and blue 24 on the 0-255 scale.

What is the CMYK value of #A51F18?

#A51F18 converts to approximately cmyk(0%, 81%, 85%, 35%). CMYK output is a mathematical approximation for planning; confirm production print colors with your printer and ICC profile.

Should text on #A51F18 be black or white?

White text is the more readable choice. #A51F18 scores 7.48:1 against white and 2.81:1 against black, and WCAG 2.2 asks for at least 4.5:1 for normal body text.

Can I write #A51F18 as a CSS color keyword?

No. #A51F18 is not one of the CSS color keywords, so it has to be written as a hex, rgb() or hsl() value. The closest keyword is firebrick (#B22222) at a CIE76 distance of 4.75, which is very hard to tell apart.

Open #A51F18 in a Tool

Hex to RGB Hex to HSL Hex to CMYK Hex to OKLCH Hex to Pantone Build a palette Make a gradient

Keep exploring: every red in the color library, the guide to shades of red, or the full color library.