Skip to content
red · warm

#643237

a dark, soft red · warm · closest name: Brown

Token name suggestion: Slate Rust

RGB
100, 50, 55
HSL
354°, 33%, 29%
CMYK
0, 50, 45, 61
Luminance
0.0527

#643237 is a dark soft red, 354° on the wheel and 21/100 on the cool side. Put white text on it (10.23:1). As text it scores 10.23:1 on white — safe at any size. Nearest name is Brown, nearest Tailwind family is stone.

hsl(354 33% 29%)rgb(100 50 55)Base step 800AAA inkWarm

At a glance

Every number on this page in one read: what #643237 is made of, how bright it looks, and which way it leans.

Hex
#643237
Hue
354°
red
Saturation
33%
soft
Lightness
29%
dark
Brightness
39%
HSV value
Perceived
27%
weighted brightness
Luminance
0.0527
WCAG relative
Temperature
Warm
21/100 cool
Color family
Red
Tone
Soft
Best ink
White
10.23:1
Closest name
Brown
ΔE2000 15.7
Chroma
24.1
LCH, 0–130ish
OKLCH L
0.384
perceptual lightness
Tailwind
stone
500 · ΔE 24.8
Web-safe
#663333
nearest of 216
Where it sits
Hue354° of 360°
Saturation33%
Lightness29%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #643237.

Temperature
Warm ← → Cool21% cool

Reads warm. Warm and cool siblings keep the same lightness, so you can swap one in without redoing your contrast maths.

Luminance by channel
Red51%
Green43%
Blue5%

Green carries most of what the eye calls brightness — that is why WCAG weights it 0.7152.

Every format

HEX#643237
HEX (8-digit)#643237ff
RGBrgb(100, 50, 55)
RGBArgba(100, 50, 55, 1)
HSLhsl(354, 33%, 29%)
HSV / HSBhsv(354, 50%, 39%)
HWBhwb(354 20% 61%)
CMYKcmyk(0%, 50%, 45%, 61%)
LABlab(27.5 23.0 7.1)
LCHlch(27.5 24.1 17.1)
OKLCHoklch(0.384 0.072 14.7)
XYZ (D65)xyz(7.09, 5.27, 4.26)
Decimal6566455
Display P3color(display-p3 0.392 0.196 0.216)
Web-safe#663333

Copy-ready code

every platformclick to select
/* CSS */
color: #643237;
background-color: #643237;
/* CSS custom property */
--brand: #643237;
/* Tailwind (arbitrary) */
class="text-[#643237] bg-[#643237]"
/* SCSS */
$brand: #643237;
/* SwiftUI */
Color(red: 0.392, green: 0.196, blue: 0.216)
/* UIKit */
UIColor(red: 0.392, green: 0.196, blue: 0.216, alpha: 1)
/* Android XML */
<color name="brand">#643237</color>
/* Android Compose */
Color(0xFF643237)
/* Flutter */
Color(0xFF643237)
/* Python / OpenCV (BGR) */
(55, 50, 100)
/* Python / PIL (RGB) */
(100, 50, 55)
/* Java AWT */
new Color(100, 50, 55)
/* .NET */
Color.FromArgb(255, 100, 50, 55)
/* OpenGL / Unity (0–1) */
(0.3922f, 0.1961f, 0.2157f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{100,50,55}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #643237 85%, white);
border-color: color-mix(in oklab, #643237 40%, transparent);
/* theme-aware in one line */
color: light-dark(#552B2F, #EBD6D8);
/* relative colour syntax */
--hover: hsl(from #643237 h s calc(l - 7));

Design tokens

The same ramp in the four formats a team actually needs. Paste one and the whole palette lands with it.

css custom propertiesclick to select
:root {
  --brand-50: #F9F5F6;
  --brand-100: #F4ECED;
  --brand-200: #E8D4D6;
  --brand-300: #DAB4B8;
  --brand-400: #C78F94;
  --brand-500: #B46971;
  --brand-600: #A3525A;
  --brand-700: #88444B;
  --brand-800: #643237;
  --brand-900: #502A2E;
  --brand-950: #321B1D;
  --brand: #643237;
  --brand-ink: #ffffff;
  --brand-surface: #FAF5F5;
  --brand-border: #E4C9CB;
  --brand-hover: #4C262A;
  --brand-pressed: #341A1D;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #241415;
    --brand-ink: #EBD6D8;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F9F5F6',
        100: '#F4ECED',
        200: '#E8D4D6',
        300: '#DAB4B8',
        400: '#C78F94',
        500: '#B46971',
        600: '#A3525A',
        700: '#88444B',
        800: '#643237',
        900: '#502A2E',
        950: '#321B1D',
        DEFAULT: '#643237',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F9F5F6,
  '100': #F4ECED,
  '200': #E8D4D6,
  '300': #DAB4B8,
  '400': #C78F94,
  '500': #B46971,
  '600': #A3525A,
  '700': #88444B,
  '800': #643237,
  '900': #502A2E,
  '950': #321B1D,
);
$brand-base: #643237;
$brand-ink: #ffffff;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F9F5F6", "$type": "color" },
      "100": { "$value": "#F4ECED", "$type": "color" },
      "200": { "$value": "#E8D4D6", "$type": "color" },
      "300": { "$value": "#DAB4B8", "$type": "color" },
      "400": { "$value": "#C78F94", "$type": "color" },
      "500": { "$value": "#B46971", "$type": "color" },
      "600": { "$value": "#A3525A", "$type": "color" },
      "700": { "$value": "#88444B", "$type": "color" },
      "800": { "$value": "#643237", "$type": "color" },
      "900": { "$value": "#502A2E", "$type": "color" },
      "950": { "$value": "#321B1D", "$type": "color" }
    },
    "brandInk": { "$value": "#ffffff", "$type": "color" }
  }
}

Best text color

Only one of black and white can be right. This is the one, with the number that proves it.

Readable at a glance#ffffff on #643237 · 10.23:1
Use #ffffffAAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 10.23:1 · recommended
AA pass · AA large pass · AAA pass
Aa
Black text · 2.05:1
AA fail · AA large fail · AAA fail
Reading the other direction: #643237 as text scores 10.23:1 on white and 2.05:1 on black.
Best tinted ink on it, if plain black or white feels flat: #F6EEEF at 8.96:1.

Make it accessible

A contrast checker tells you that you failed. This tells you what to ship instead — same hue, same saturation, lightness moved only as far as WCAG demands.

The quick fox
#643237 · 10.23:1
AA on whitealready passes
#643237
The quick fox
#643237 · 10.23:1
AAA on whitealready passes
#643237
The quick fox
#AE5D65 · 4.55:1
AA on black+23% L
#AE5D65
The quick fox
#C2868C · 7.08:1
AAA on black+35% L
#C2868C

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #643237 is enough for headings on white. Non-text elements such as icons, chart strokes and focus rings also sit at 3:1 under WCAG 2.2 (1.4.11).

Accessibility — WCAG contrast

Aa
#643237 on white: 10.23:1
AA ✓ pass · AA-large · AAA
Aa
#643237 on black: 2.05:1
AA ✗ fail · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #643237 as text on that neutral, and that neutral as text on #643237.

NeutralRatioBoth directions
White10.23:1AaAa
Slate 509.78:1AaAa
Slate 1009.34:1AaAa
Slate 2008.30:1AaAa
Slate 3006.89:1AaAa
Slate 4003.99:1AaAa
Slate 5002.15:1AaAa
Slate 6001.35:1AaAa
Slate 7001.01:1AaAa
Slate 8001.43:1AaAa
Slate 9001.75:1AaAa
Black2.05:1AaAa
Colour vision deficiency
true color
protanopia · #3C3B37
deuteranopia · #484536
tritanopia · #6C2C34

Roughly one man in twelve has some form of colour vision deficiency. If any of the three panels above is hard to tell apart from a neighbouring colour in your palette, add a shape, an icon or a label so the meaning does not rest on hue alone.

Color scale — 50 to 950

A Tailwind-shaped ramp built around this exact hex. #643237 is pinned to step 800; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F9F5F6
#F4ECED
#E8D4D6
#DAB4B8
#C78F94
#B46971
#A3525A
#88444B
#643237
#502A2E
#321B1D
Base = 800Lightest = 50 · #F9F5F6Darkest = 950 · #321B1DText step on white = 600
Perceptual ramp — OKLCH

The same eleven steps expressed in OKLCH, where equal lightness numbers actually look equally spaced. HSL ramps go muddy in the yellows and washed out in the blues; this one does not. Modern browsers render it natively — the hex ramp above is the fallback.

50100200300400500600700800900950
oklch tokensclick to select
:root {
  --brand-50: oklch(0.97 0.018 14.7);
  --brand-100: oklch(0.94 0.029 14.7);
  --brand-200: oklch(0.88 0.043 14.7);
  --brand-300: oklch(0.80 0.056 14.7);
  --brand-400: oklch(0.72 0.066 14.7);
  --brand-500: oklch(0.64 0.072 14.7);
  --brand-600: oklch(0.56 0.072 14.7);
  --brand-700: oklch(0.48 0.068 14.7);
  --brand-800: oklch(0.40 0.060 14.7);
  --brand-900: oklch(0.32 0.050 14.7);
  --brand-950: oklch(0.24 0.040 14.7);
}

Colors that work with #643237

Not a palette — a role sheet. Each swatch answers one question you will hit while building the component.

Text on it#ffffff
White wins here
Surface#FAF5F5
Tinted page background
Border#E4C9CB
Hairlines and dividers
Muted text#994D54
Captions on the surface
Accent#2F6753
Second voice, not a rival
Dark variant#552B2F
Hover, pressed, headers
Light variant#F6EEEF
Selected rows, tints
Dark surface#241415
Dark-mode background
Hover#4C262A
One step down in lightness
Pressed#341A1D
Two steps down
Disabled#9E686D
Chroma pulled out
Focus ring#7A3038
Offset from the fill so it reads
Light mode
Everything in its place

Surface, border, heading and body all derive from this one hue, so the screen stays coherent without a second palette.

Primary actionSecondaryBadge
Dark mode
Same hue, inverted

Lightness flips, hue holds. The accent stays the anchor in both themes.

Primary actionSecondaryAccent

In real components

The same eight roles, wired into the interface patterns you will actually build with them. Every state below is a computed value, not a mock-up.

Buttons and states
Save changesHoverPressedDisabled
OutlineSubtleLinkFocused
Form field
you@company.com

Focus ring uses the light variant so the field still reads as one shape.

Send me product updates
Notice
Your export is ready

The file stays available for seven days. Download it before it expires.

NewBetaDraft
Data
Storage used68%
Acme LtdActive
NorthwindTrial
GlobexActive

How to use #643237

Derived from its contrast, chroma and lightness — not from taste.

Works well for
  • Body text and links on white
  • Charts, tags and secondary surfaces
  • Headers, footers and dark-mode surfaces
  • Brand accents, badges and data highlights
Use with care
  • Text on black or near-black surfaces
  • Black text placed on it
  • Status meaning — pair it with an icon or label, never colour alone
  • Pairing with a same-lightness hue — edges vibrate
Minimum size as text on white
Any size
Safe as a fill behind white type
Yes
Safe as a 1px border on white
Yes

Meaning and mood

What a colour in this family tends to signal, and how this particular chroma and lightness change the reading.

urgentappetisingboldphysical

Red arrives before the rest of the page does. It raises attention and appetite, which is why it runs food, sport and clearance pricing.

The muted chroma softens the association — it reads considered rather than loud, which suits long-form and data-heavy screens. The low lightness adds weight and formality.

Worth knowing

It is also the universal error colour. Use it as a brand accent and users may read a warning that is not there.

Reads as
  • FormalityHigh
  • EnergyMedium
  • Weight71/100
  • TemperatureWarm
  • ApproachabilityHigh

Colour associations are cultural and vary by market. Treat these as a starting point for a conversation with your audience, not a finding about them.

Similar colors

One move away from this hex in each direction. Every swatch is its own page.

Color relationships

The wheel positions with their names attached, so you can grab the one you actually need.

Complementary#32645F
Analogous left#643250
Analogous right#644632
Split-complement 1#326446
Split-complement 2#325064
Triadic 1#376432
Triadic 2#323764
Tetradic#506432
On the wheel
Base+30°−30°+120°+240°+180°354°

#643237 sits at 354°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red39.2%
Green19.6%
Blue21.6%
R · 0–255
100
0x64
G · 0–255
50
0x32
B · 0–255
55
0x37

CMYK percentages

Cyan0.0%
Magenta50.0%
Yellow45.0%
Key (black)60.8%

Total ink coverage is 156%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#643237 text on a black background

contrast 2.05:1

Card sample

#643237 text on a white background

contrast 10.23:1

Card sample

#643237 on grey

9.34:1

#643237 on its own surface

9.47:1

#643237 on its dark surface

1.73:1

CSS3 live lab

Text font color

The quick brown fox

color: #643237;
Background color
Panel with #643237 background
background-color: #643237;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #643237;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(100, 50, 55, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(100, 50, 55, 0.45);
Border & gradient
Gradient panel
border: 3px solid #643237;
background: linear-gradient(135deg, #643237, #644E32);
Gradient text

Gradient headline

background: linear-gradient(90deg, #643237, #645B32);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #643237;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #643237;
caret-color: #643237;
Left rule
Pull quote or callout
border-left: 4px solid #643237;
Ring + tint
Selected chip
background: #F6EEEF;
box-shadow: inset 0 0 0 2px #643237;
Conic badge
68%
background: conic-gradient(#643237 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #643237 over white; the bottom row is the same alpha over a checkerboard, so you can see what survives on a photo or a video.

Bottom row of hexes is the flattened result over white — use those when a design tool refuses transparency, or when you need a solid fallback.

alpha in every syntaxclick to select
rgba(100, 50, 55, 0.5)
rgb(100 50 55 / 50%)
#64323780
hsl(354 33% 29% / 50%)
color-mix(in srgb, #643237 50%, transparent)
Alpha8-digit hexFlat on white
10%#6432371a#F0EBEB
20%#64323733#E0D6D7
40%#64323766#C1ADAF
60%#64323799#A28487
80%#643237cc#835B5F

Gradients from #643237

Six recipes, each built from this hex and shown with the exact CSS that produced it.

Elevation
Same hue, three lightnesses — safe anywhere
background: linear-gradient(135deg, #8D464D, #643237 45%, #552B2F);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #643237, #504228);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #643237, #32645F);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #A15159 0%, #643237 45%, #552B2F 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #FAF5F5, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #864371 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #78593C 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #552B2F 0%, transparent 65%), #643237;

Monochromatic scale

Palettes built from #643237

Shades — darker

Tints — lighter

Tones — desaturated

Color harmonies

Nearest named colors

Ranked with CIEDE2000 across all 139 CSS keywords. Under ΔE 2 the eye stops telling them apart; over ΔE 10 they are plainly different colors.

#643237 in the real world

Where a color in this family tends to land, and the interface roles it is usually asked to play.

Industries
Food and drinkEntertainmentRetailSport
Common UI roles
ButtonsLinksFocus statesCharts
Print note

Converts to four-color process without much drama. Proof it anyway.

On screens

Holds up across typical panel gamma. Still worth checking on an uncalibrated laptop, where mid-tones shift most.

In dark mode

Too dim on dark surfaces at 2.05:1 — lift it to #AE5D65 for body text, or reserve it for fills.

Explore nearby colors

Small, deliberate steps away from this hex — useful when you are hunting for the version of a colour that finally feels right.

#643237, answered

What color is #643237?

#643237 is a dark soft red, closest to Brown (ΔE2000 15.7). It sits at 354° on the hue wheel with 33% saturation and 29% lightness, which reads as warm.

What is the RGB value of #643237?

rgb(100, 50, 55) — 100 red, 50 green and 55 blue out of 255, or 39.2% / 19.6% / 21.6% by channel.

What is #643237 in HSL and HSV?

hsl(354, 33%, 29%) and hsv(354, 50%, 39%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #643237 a light or a dark color?

It is a dark color. Relative luminance is 0.0527 and perceived brightness is 27%, so white text on it reaches 10.23:1.

Should I use black or white text on #643237?

White. It scores 10.23:1 against #643237, versus 2.05:1 for black — AAA at any size.

Is #643237 accessible on a white background?

#643237 on white scores 10.23:1, which clears AAA at every size.

What is the complementary color of #643237?

#32645F sits directly opposite on the wheel. Softer options are the split-complements #326446 and #325064, which give the same contrast with far less vibration.

What colors go well with #643237?

For interface work: #FAF5F5 as the surface, #E4C9CB for borders, #994D54 for secondary text, #2F6753 as an accent and #552B2F for hover and pressed states. For a palette, the analogous pair #643250 and #644632 stays calm, while #32645F is the loudest partner.

What is #643237 in CMYK for printing?

cmyk(0%, 50%, 45%, 61%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #643237 warm or cool?

Warm — it scores 21 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #643F32; nudged cooler, #653149.

Which Tailwind color is closest to #643237?

The stone family — its 500 step is #78716c, ΔE2000 24.8 away. That is a visible difference, so define #643237 as a custom token rather than reaching for the built-in.

How do I use #643237 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#643237] or text-[#643237], or register the whole ramp under theme.extend.colors.brand so you get bg-brand-500 and friends. The generated 50–950 scale on this page is ready to paste into your config.

What is #643237 with 50% opacity?

rgba(100, 50, 55, 0.5), or #64323780 in eight-digit hex. Over white that composites to #B2999B; over black, #32191C.

Is #643237 a web-safe color?

No. The nearest web-safe colour is #663333, ΔE2000 2.3 away. The palette only matters for legacy displays and some email clients now.

What does the color #643237 mean?

As a red, it reads urgent, appetising, bold. Red arrives before the rest of the page does. It raises attention and appetite, which is why it runs food, sport and clearance pricing. At this moderate chroma the association is present but not shouted.

What gradient works with #643237?

The safest is same-hue elevation: linear-gradient(135deg, #8D464D, #643237 45%, #552B2F). For more colour, a short hue run to #504228 keeps it rich without turning muddy.

Work with #643237 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #643237 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.