#18183B
Closest named color: Rich Black (#0D1B2A). oklch(23.1% 0.066 280), rgb(24, 24, 59).
Aa
White text reads best on this color (17.03:1).
About this color
#18183B is a very dark, muted blue. In OKLCH its lightness is 23%, its chroma 0.066 and its hue 280°. Its hue sits on the cool side of the wheel. The nearest named color is Rich Black (#0D1B2A), ΔE 0.041 away. White text reads best on it, at 17.03:1.
| Hue family | Blues |
| Lightness | very dark (23%) |
| Chroma | muted (0.066) |
| Temperature | cool |
| Nearest name | Rich Black (#0D1B2A) |
| Black text | 1.23:1 |
| White text | 17.03:1 |
Values
| HEX | #18183B |
| RGB | rgb(24, 24, 59) |
| HSL | hsl(240, 42%, 16%) |
| OKLCH | oklch(23.1% 0.066 280) |
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 #18183B | 17.03:1 | AAA | Lc -106.2 | Preferred for body text |
| Black text on #18183B | 1.23:1 | Fails | Lc 0.0 | Not readable |
| #18183B text on white | 17.03:1 | AAA | Lc 103.8 | Preferred for body text |
| #18183B text on black | 1.23:1 | Fails | Lc 0.0 | Not readable |
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 950.
-
Step 50
50
#F4F5FD
oklch(97.2% 0.011 280.5)
-
Step 100
100
#E6E9F9
oklch(93.6% 0.022 277.5)
-
Step 200
200
#D3D7F6
oklch(88.6% 0.043 279.7)
-
Step 300
300
#B6BCF3
oklch(81% 0.078 279.7)
-
Step 400
400
#9297ED
oklch(70.7% 0.125 280.1)
-
Step 500
500
#797BE7
oklch(63.2% 0.159 280)
-
Step 600
600
#6361D5
oklch(55.6% 0.173 279.9)
-
Step 700
700
#524FB8
oklch(49% 0.161 279.9)
-
Step 800
800
#434295
oklch(42.7% 0.133 279.7)
-
Step 900
900
#383977
oklch(37.8% 0.103 279.5)
-
Step 950
950 (this color)
#18183B
oklch(23.1% 0.066 280)
#18183B 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) | #071D3C | 0.026 |
| Deuteranopia (no green cones) | #041B3A | 0.028 |
| Tritanopia (no blue cones) | #0A2026 | 0.058 |
| Achromatopsia (no color) | #1C1C1C | 0.066 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #18183B
#18183B
oklch(23.1% 0.066 280)
- #231D00
#231D00
oklch(23.1% 0.048 98.3)
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 #18183B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rich Black #0D1B2A ΔE 0.041
- Oxford Blue #1B263B ΔE 0.047
- Navy Blue #001146 ΔE 0.049
- Dark #1B2431 ΔE 0.049
- Dark Indigo #1F0954 ΔE 0.057
- Midnight Purple #280137 ΔE 0.063
- Jet #212529 ΔE 0.066
- Very Dark Purple #2A0134 ΔE 0.066
Use #18183B 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.