#B51100
Closest named color: Rufous (#AE2012). oklch(49.1% 0.194 30.5), rgb(181, 17, 0).
Aa
White text reads best on this color (6.89:1).
About this color
#B51100 is a medium-dark, vivid red. In OKLCH its lightness is 49%, its chroma 0.194 and its hue 30°. Its hue sits on the warm side of the wheel. The nearest named color is Rufous (#AE2012), ΔE 0.016 away. White text reads best on it, at 6.89:1.
| Hue family | Reds |
| Lightness | medium-dark (49%) |
| Chroma | vivid (0.194) |
| Temperature | warm |
| Nearest name | Rufous (#AE2012) |
| Black text | 3.04:1 |
| White text | 6.89:1 |
Values
| HEX | #B51100 |
| RGB | rgb(181, 17, 0) |
| HSL | hsl(6, 100%, 35%) |
| OKLCH | oklch(49.1% 0.194 30.5) |
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 #B51100 | 6.89:1 | AA | Lc -86.7 | Fine for body text |
| Black text on #B51100 | 3.04:1 | AA large text | Lc 22.5 | Dividers and decoration only |
| #B51100 text on white | 6.89:1 | AA | Lc 81.6 | Fine for body text |
| #B51100 text on black | 3.04:1 | AA large text | Lc -20.3 | 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
#FCE4DF
oklch(93.7% 0.027 31.7)
-
Step 200
200
#FACDC5
oklch(88.5% 0.052 29.9)
-
Step 300
300
#F7AA9C
oklch(80.9% 0.094 30.6)
-
Step 400
400
#EF7866
oklch(70.6% 0.15 30.1)
-
Step 500
500
#E64E3A
oklch(63.1% 0.192 30.6)
-
Step 600
600
#D22412
oklch(55.6% 0.209 30.3)
-
Step 700
700 (this color)
#B51100
oklch(49.1% 0.194 30.5)
-
Step 800
800
#931608
oklch(42.7% 0.161 30.5)
-
Step 900
900
#761D12
oklch(37.7% 0.125 30.6)
-
Step 950
950
#46130C
oklch(27.1% 0.08 30.7)
#B51100 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) | #4E4400 | 0.211 |
| Deuteranopia (no green cones) | #746600 | 0.186 |
| Tritanopia (no blue cones) | #C80012 | 0.040 |
| Achromatopsia (no color) | #5A5A5A | 0.196 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #B51100
#B51100
oklch(49.1% 0.194 30.5)
- #006D7B
#006D7B
oklch(49% 0.085 210.2)
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 #B51100, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rufous #AE2012 ΔE 0.016
- Firebrick #B22222 ΔE 0.020
- Scarlet #BE0119 ΔE 0.023
- Rust Red #AA2704 ΔE 0.026
- Rusty Red #AF2F0D ΔE 0.030
- Brown #A52A2A ΔE 0.039
- Lipstick Red #C0022F ΔE 0.041
- Burnt Red #9F2305 ΔE 0.044
Use #B51100 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.