#00243B
Closest named color: Oxford Blue (#1B263B). oklch(24.9% 0.059 241.9), rgb(0, 36, 59).
Aa
White text reads best on this color (15.96:1).
About this color
#00243B is a very dark, muted blue. In OKLCH its lightness is 25%, its chroma 0.059 and its hue 242°. Its hue sits on the cool side of the wheel. The nearest named color is Oxford Blue (#1B263B), ΔE 0.032 away. White text reads best on it, at 15.96:1.
| Hue family | Blues |
| Lightness | very dark (25%) |
| Chroma | muted (0.059) |
| Temperature | cool |
| Nearest name | Oxford Blue (#1B263B) |
| Black text | 1.31:1 |
| White text | 15.96:1 |
Values
| HEX | #00243B |
| RGB | rgb(0, 36, 59) |
| HSL | hsl(203, 100%, 12%) |
| OKLCH | oklch(24.9% 0.059 241.9) |
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 #00243B | 15.96:1 | AAA | Lc -105.3 | Preferred for body text |
| Black text on #00243B | 1.31:1 | Fails | Lc 0.0 | Not readable |
| #00243B text on white | 15.96:1 | AAA | Lc 102.6 | Preferred for body text |
| #00243B text on black | 1.31:1 | 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
#F0F6FB
oklch(97% 0.009 242.8)
-
Step 100
100
#DFECF7
oklch(93.7% 0.02 243.4)
-
Step 200
200
#C4DDF1
oklch(88.5% 0.038 242.2)
-
Step 300
300
#99C7EA
oklch(80.9% 0.069 241.5)
-
Step 400
400
#5BA9E0
oklch(70.7% 0.112 241.4)
-
Step 500
500
#1892D8
oklch(63.2% 0.143 241.8)
-
Step 600
600
#007AB9
oklch(55.5% 0.132 242.1)
-
Step 700
700
#00679C
oklch(49.2% 0.116 241.5)
-
Step 800
800
#005481
oklch(42.7% 0.101 241.9)
-
Step 900
900
#00466C
oklch(37.7% 0.089 241.5)
-
Step 950
950 (this color)
#00243B
oklch(24.9% 0.059 241.9)
#00243B 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) | #19253C | 0.028 |
| Deuteranopia (no green cones) | #101F3B | 0.021 |
| Tritanopia (no blue cones) | #002A2C | 0.041 |
| Achromatopsia (no color) | #222222 | 0.059 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #00243B
#00243B
oklch(24.9% 0.059 241.9)
- #341A00
#341A00
oklch(24.9% 0.057 62.6)
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 #00243B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Oxford Blue #1B263B ΔE 0.032
- Dark #1B2431 ΔE 0.034
- Rich Black #0D1B2A ΔE 0.040
- Jet #212529 ΔE 0.051
- Navy Blue #001146 ΔE 0.064
- Space Cadet #2B2D42 ΔE 0.067
- Marine #042E60 ΔE 0.073
- Gunmetal #293241 ΔE 0.074
Use #00243B 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.