#B21B00
Closest named color: Rufous (#AE2012). oklch(49% 0.187 31.7), rgb(178, 27, 0).
Aa
White text reads best on this color (6.88:1).
About this color
#B21B00 is a medium-dark, vivid red. In OKLCH its lightness is 49%, its chroma 0.187 and its hue 32°. Its hue sits on the warm side of the wheel. The nearest named color is Rufous (#AE2012), ΔE 0.010 away. White text reads best on it, at 6.88:1.
| Hue family | Reds |
| Lightness | medium-dark (49%) |
| Chroma | vivid (0.187) |
| Temperature | warm |
| Nearest name | Rufous (#AE2012) |
| Black text | 3.04:1 |
| White text | 6.88:1 |
Values
| HEX | #B21B00 |
| RGB | rgb(178, 27, 0) |
| HSL | hsl(9, 100%, 35%) |
| OKLCH | oklch(49% 0.187 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 #B21B00 | 6.88:1 | AA | Lc -87.0 | Fine for body text |
| Black text on #B21B00 | 3.04:1 | AA large text | Lc 22.2 | Dividers and decoration only |
| #B21B00 text on white | 6.88:1 | AA | Lc 81.9 | Fine for body text |
| #B21B00 text on black | 3.04:1 | AA large text | Lc -20.0 | 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
#FDF3F0
oklch(97.1% 0.012 37.4)
-
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
#F5AB9C
oklch(80.8% 0.09 31.8)
-
Step 400
400
#ED7B66
oklch(70.8% 0.145 31.8)
-
Step 500
500
#E3523A
oklch(63.1% 0.185 31.8)
-
Step 600
600
#CF2C12
oklch(55.6% 0.202 31.7)
-
Step 700
700 (this color)
#B21B00
oklch(49% 0.187 31.7)
-
Step 800
800
#911C09
oklch(42.8% 0.155 31.7)
-
Step 900
900
#742012
oklch(37.7% 0.12 32)
-
Step 950
950
#45140C
oklch(27% 0.077 31.7)
#B21B00 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) | #504500 | 0.200 |
| Deuteranopia (no green cones) | #736600 | 0.179 |
| Tritanopia (no blue cones) | #C50019 | 0.042 |
| Achromatopsia (no color) | #5A5A5A | 0.188 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #B21B00
#B21B00
oklch(49% 0.187 31.7)
- #006D7C
#006D7C
oklch(49% 0.085 211.2)
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 #B21B00, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rufous #AE2012 ΔE 0.010
- Rust Red #AA2704 ΔE 0.018
- Firebrick #B22222 ΔE 0.019
- Rusty Red #AF2F0D ΔE 0.022
- Scarlet #BE0119 ΔE 0.030
- Brown #A52A2A ΔE 0.034
- Burnt Red #9F2305 ΔE 0.038
- Brick #A03623 ΔE 0.043
Use #B21B00 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.