#B31309
Closest named color: Rufous (#AE2012). oklch(48.8% 0.191 29.6), rgb(179, 19, 9).
Aa
White text reads best on this color (6.96:1).
About this color
#B31309 is a medium-dark, vivid red. In OKLCH its lightness is 49%, its chroma 0.191 and its hue 30°. Its hue sits on the warm side of the wheel. The nearest named color is Rufous (#AE2012), ΔE 0.012 away. White text reads best on it, at 6.96:1.
| Hue family | Reds |
| Lightness | medium-dark (49%) |
| Chroma | vivid (0.191) |
| Temperature | warm |
| Nearest name | Rufous (#AE2012) |
| Black text | 3.01:1 |
| White text | 6.96:1 |
Values
| HEX | #B31309 |
| RGB | rgb(179, 19, 9) |
| HSL | hsl(4, 90%, 37%) |
| OKLCH | oklch(48.8% 0.191 29.6) |
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 #B31309 | 6.96:1 | AA | Lc -87.1 | Fine for body text |
| Black text on #B31309 | 3.01:1 | AA large text | Lc 22.1 | Dividers and decoration only |
| #B31309 text on white | 6.96:1 | AA | Lc 82.0 | Fine for body text |
| #B31309 text on black | 3.01:1 | AA large text | Lc -19.9 | 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
#FEF3F1
oklch(97.2% 0.012 29.9)
-
Step 100
100
#FBE4E0
oklch(93.6% 0.026 29.4)
-
Step 200
200
#F9CDC6
oklch(88.4% 0.051 28.7)
-
Step 300
300
#F7AA9E
oklch(80.9% 0.093 29.1)
-
Step 400
400
#EE7968
oklch(70.7% 0.148 29.8)
-
Step 500
500
#E54F3E
oklch(63.1% 0.189 29.7)
-
Step 600
600
#D1271A
oklch(55.7% 0.206 29.6)
-
Step 700
700 (this color)
#B31309
oklch(48.8% 0.191 29.6)
-
Step 800
800
#92180F
oklch(42.7% 0.158 29.6)
-
Step 900
900
#751E15
oklch(37.7% 0.122 29.8)
-
Step 950
950
#45130E
oklch(26.9% 0.078 28.9)
#B31309 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) | #4D4403 | 0.209 |
| Deuteranopia (no green cones) | #736500 | 0.185 |
| Tritanopia (no blue cones) | #C60015 | 0.039 |
| Achromatopsia (no color) | #595959 | 0.193 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #B31309
#B31309
oklch(48.8% 0.191 29.6)
- #006C7A
#006C7A
oklch(48.7% 0.084 210.3)
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 #B31309, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rufous #AE2012 ΔE 0.012
- Firebrick #B22222 ΔE 0.017
- Rust Red #AA2704 ΔE 0.024
- Scarlet #BE0119 ΔE 0.025
- Rusty Red #AF2F0D ΔE 0.029
- Brown #A52A2A ΔE 0.035
- Burnt Red #9F2305 ΔE 0.041
- Lipstick Red #C0022F ΔE 0.041
Use #B31309 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.