#B51D02
Closest named color: Rufous (#AE2012). oklch(49.7% 0.188 31.7), rgb(181, 29, 2).
Aa
White text reads best on this color (6.68:1).
About this color
#B51D02 is a medium-dark, vivid red. In OKLCH its lightness is 50%, its chroma 0.188 and its hue 32°. Its hue sits on the warm side of the wheel. The nearest named color is Rufous (#AE2012), ΔE 0.015 away. White text reads best on it, at 6.68:1.
| Hue family | Reds |
| Lightness | medium-dark (50%) |
| Chroma | vivid (0.188) |
| Temperature | warm |
| Nearest name | Rufous (#AE2012) |
| Black text | 3.14:1 |
| White text | 6.68:1 |
Values
| HEX | #B51D02 |
| RGB | rgb(181, 29, 2) |
| HSL | hsl(9, 98%, 36%) |
| OKLCH | oklch(49.7% 0.188 31.7) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #B51D02 | 6.68:1 | AA | Lc -86.2 | Fine for body text |
| Black text on #B51D02 | 3.14:1 | AA large text | Lc 23.0 | Dividers and decoration only |
| #B51D02 text on white | 6.68:1 | AA | Lc 81.1 | Fine for body text |
| #B51D02 text on black | 3.14:1 | AA large text | Lc -20.8 | Dividers and decoration only |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 700.
-
Step 50
50
#FEF3F0
oklch(97.2% 0.013 35.7)
-
Step 100
100
#FBE4DF
oklch(93.6% 0.026 32.2)
-
Step 200
200
#F9CEC5
oklch(88.6% 0.05 31.8)
-
Step 300
300
#F6AB9C
oklch(80.9% 0.092 31.7)
-
Step 400
400
#ED7A65
oklch(70.6% 0.146 31.7)
-
Step 500
500
#E45139
oklch(63.1% 0.187 31.8)
-
Step 600
600
#CF2B10
oklch(55.5% 0.203 31.7)
-
Step 700
700 (this color)
#B51D02
oklch(49.7% 0.188 31.7)
-
Step 800
800
#911B08
oklch(42.7% 0.156 31.7)
-
Step 900
900
#751F12
oklch(37.8% 0.122 31.5)
-
Step 950
950
#45140C
oklch(27% 0.077 31.7)
#B51D02 with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #514700 | 0.203 |
| Deuteranopia (no green cones) | #766800 | 0.180 |
| Tritanopia (no blue cones) | #C8001B | 0.042 |
| Achromatopsia (no color) | #5C5C5C | 0.190 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #B51D02
#B51D02
oklch(49.7% 0.188 31.7)
- #006F7F
#006F7F
oklch(49.7% 0.087 212)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #B51D02, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rufous #AE2012 ΔE 0.015
- Firebrick #B22222 ΔE 0.018
- Rusty Red #AF2F0D ΔE 0.021
- Rust Red #AA2704 ΔE 0.022
- Scarlet #BE0119 ΔE 0.027
- Brown #A52A2A ΔE 0.038
- Lipstick Red #C0022F ΔE 0.044
- Burnt Red #9F2305 ΔE 0.045
Use #B51D02 in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.