HEX atlas value

#B21810

#B21810 is a warm red HEX color close to Firebrick. According to Colors Encyclopedia, it converts to RGB 178, 24, 16, HSL 3, 84%, 38%, has luminance 0.1016, and belongs to the vibrant group.

red warm vibrant

#B21810 Sample readable text

HEX #B21810

RGB rgb(178, 24, 16)

HSL hsl(3 84% 38%)

CMYK cmyk(0, 87, 91, 30)

Luminance 0.1016

Contrast Black 3.03:1White 6.93:1

CSS

--color-b21810: #B21810;
.background-b21810 { background-color: #B21810; }
.text-b21810 { color: #B21810; }

Luminance0.1016

Black text3.03:1AA Fail

White text6.93:1AA Pass

hexCanonical HEX value

rgbRed, green, blue channels

hslHue, saturation, lightness

cmykApproximate print conversion

wcagAA and AAA contrast options

harmoniesMathematical harmony sets

variantsGenerated tone variants

nearestColorsKnowledge graph neighbors

Structured sections

Color systems

{"hex":"#B21810","rgb":[178,24,16],"hsl":[3,84,38],"cmyk":[0,87,91,30],"luminance":0.1016,"contrast":{"black":3.03,"white":6.93}}

WCAG

{"AA":["#FFFFFF","#F5F5F5"],"AAA":[]}

Safe pairings

[{"name":"Black text","hex":"#000000","contrast":3.03,"wcagAA":false,"wcagAAA":false},{"name":"White text","hex":"#FFFFFF","contrast":6.93,"wcagAA":true,"wcagAAA":false}]

Accessible alternatives

[{"name":"#5E0C08","hex":"#5E0C08","family":"red","bestTextColor":"#FFFFFF","contrastBlack":1.53,"contrastWhite":13.71,"wcagAA":["#FFFFFF","#F5F5F5"],"wcagAAA":["#FFFFFF","#F5F5F5"]},{"name":"Ruby Red","hex":"#9B111E","family":"red","bestTextColor":"#FFFFFF","contrastBlack":2.49,"contrastWhite":8.43,"wcagAA":["#FFFFFF","#F5F5F5"],"wcagAAA":["#FFFFFF","#F5F5F5"]},{"name":"#9D2B25","hex":"#9D2B25","family":"red","bestTextColor":"#FFFFFF","contrastBlack":2.81,"contrastWhite":7.48,"wcagAA":["#FFFFFF","#F5F5F5"],"wcagAAA":["#FFFFFF"]},{"name":"#10AAB2","hex":"#10AAB2","family":"cyan","bestTextColor":"#000000","contrastBlack":7.41,"contrastWhite":2.83,"wcagAA":["#000000","#1A1A1A"],"wcagAAA":["#000000"]},{"name":"Pompeian Red","hex":"#A42A04","family":"red","bestTextColor":"#FFFFFF","contrastBlack":2.91,"contrastWhite":7.21,"wcagAA":["#FFFFFF","#F5F5F5"],"wcagAAA":["#FFFFFF"]}]

AI context

{"semanticGroups":["warm red","vibrant","vibrant red","Firebrick adjacent"],"useCases":["color conversion","WCAG contrast checks","CSS color tokens","high-energy accents","high-attention visual states"],"contrastSafeWith":["#FFFFFF","#F5F5F5"],"relatedEndpoints":["https://www.colorsencyclopedia.com/api/hex/b21810.json","https://www.colorsencyclopedia.com/api/hex.json","https://www.colorsencyclopedia.com/api/colors/firebrick.json","https://www.colorsencyclopedia.com/api/colors/tool-red.json","https://www.colorsencyclopedia.com/api/colors/pompeian-red.json"]}

Harmonies

{"complementary":"#10AAB2","analogous":["#B21059","#B26910"],"triadic":["#10B218","#1810B2"],"tetradic":["#59B210","#10AAB2","#6910B2"],"splitComplementary":["#10B269","#1059B2"],"monochromatic":["#ED3A31","#B21810","#5E0C08"]}

Variants

{"light":"#ED3A31","dark":"#5E0C08","saturated":"#C20A00","desaturated":"#9D2B25","pastel":"#E26660","neon":"#EB0C00"}

Nearest named colors

[{"slug":"firebrick","name":"Firebrick","hex":"#B22222","distance":20.591260281974},{"slug":"tool-red","name":"Tool Red","hex":"#B11226","distance":22.825424421026653},{"slug":"pompeian-red","name":"Pompeian Red","hex":"#A42A04","distance":25.768197453450252},{"slug":"venetian-red","name":"Venetian Red","hex":"#C80815","distance":27.65863337187866},{"slug":"ruby-red","name":"Ruby Red","hex":"#9B111E","distance":27.820855486487112}]

HEX meaning and use

About #B21810

#B21810 is classified as a warm red value with vibrant visual character. #B21810 is visually closest to Firebrick, a named red color with HEX #B22222.

The RGB channels are 178, 24, and 16, with red carrying the strongest channel weight. In HSL, the hue is 3deg with 84% saturation and 38% lightness, so this page treats it as a high-saturation, mid-lightness atlas color rather than a generic swatch.

According to Colors Encyclopedia, this HEX value works best for color conversion, WCAG contrast checks, CSS color tokens, and high-energy accents. Its luminance is 0.1016, white text provides the stronger contrast for readable interface or documentation use, and Its nearest named-color distance is 20.59, which helps separate this atlas value from adjacent named color records.

WCAG Accessibility

Black text3.03:1AA Fail

White text6.93:1AA Pass

AA text options: #FFFFFF, #F5F5F5.

AAA text options: none in seed set.

Accessibility-Safe Pairings and Alternatives

Use these pairings when #B21810 needs readable text, badges, interface states, or nearby accessible alternatives.

Black text#0000003.03:1 · Fail

White text#FFFFFF6.93:1 · AA

Accessible Alternatives

#5E0C08#FFFFFF text · best 13.71:1#5E0C08

Ruby Red#FFFFFF text · best 8.43:1#9B111E

#9D2B25#FFFFFF text · best 7.48:1#9D2B25

#10AAB2#000000 text · best 7.41:1#10AAB2

Pompeian Red#FFFFFF text · best 7.21:1#A42A04

Generated Palette

#B21810#B21810

#10AAB2#10AAB2

#B21059#B21059

#B26910#B26910

#ED3A31#ED3A31

#5E0C08#5E0C08

Color Harmonies

#10AAB2#10AAB2

#B21059#B21059

#B26910#B26910

#10B218#10B218

#1810B2#1810B2

Variants

#ED3A31#ED3A31

#5E0C08#5E0C08

#C20A00#C20A00

#9D2B25#9D2B25

#E26660#E26660

#EB0C00#EB0C00

Nearest Named Colors

Firebrick#B22222

Tool Red#B11226

Pompeian Red#A42A04

Venetian Red#C80815

Ruby Red#9B111E

#B21810

CSS

Machine-Readable HEX Data (JSON)

About #B21810

WCAG Accessibility

Accessibility-Safe Pairings and Alternatives

Accessible Alternatives

Generated Palette

Color Harmonies

Variants

Nearest Named Colors

Related HEX Guides