#183C69
Closest named color: Marine Blue (#01386A). oklch(35.5% 0.089 255.5), rgb(24, 60, 105).
Aa
White text reads best on this color (11.11:1).
About this color
#183C69 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.089 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Marine Blue (#01386A), ΔE 0.021 away. White text reads best on it, at 11.11:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.089) |
| Temperature | cool |
| Nearest name | Marine Blue (#01386A) |
| Black text | 1.88:1 |
| White text | 11.11:1 |
Values
| HEX | #183C69 |
| RGB | rgb(24, 60, 105) |
| HSL | hsl(213, 63%, 25%) |
| OKLCH | oklch(35.5% 0.089 255.5) |
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 #183C69 | 11.11:1 | AAA | Lc -99.3 | Preferred for body text |
| Black text on #183C69 | 1.88:1 | Fails | Lc 8.5 | Not readable |
| #183C69 text on white | 11.11:1 | AAA | Lc 95.4 | Preferred for body text |
| #183C69 text on black | 1.88:1 | 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 900.
-
Step 50
50
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E2EBF7
oklch(93.7% 0.019 255.5)
-
Step 200
200
#C9DBF2
oklch(88.5% 0.037 254.6)
-
Step 300
300
#A4C3EC
oklch(80.9% 0.067 255.5)
-
Step 400
400
#73A3E2
oklch(70.7% 0.106 255.6)
-
Step 500
500
#4D8BDA
oklch(63.2% 0.136 255.4)
-
Step 600
600
#2F73C7
oklch(55.6% 0.147 255.5)
-
Step 700
700
#2160AC
oklch(49.1% 0.137 255.5)
-
Step 800
800
#1D4F8B
oklch(42.7% 0.113 255.1)
-
Step 900
900 (this color)
#183C69
oklch(35.5% 0.089 255.5)
-
Step 950
950
#122741
oklch(27% 0.056 254.8)
#183C69 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) | #27406B | 0.022 |
| Deuteranopia (no green cones) | #1A3868 | 0.012 |
| Tritanopia (no blue cones) | #00474D | 0.070 |
| Achromatopsia (no color) | #3C3C3C | 0.089 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183C69
#183C69
oklch(35.5% 0.089 255.5)
- #523500
#523500
oklch(35.5% 0.075 75.2)
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 #183C69, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Marine Blue #01386A ΔE 0.021
- Twilight Blue #0A437A ΔE 0.033
- Prussian Blue #1D3557 ΔE 0.035
- Dark Grey Blue #29465B ΔE 0.049
- Dark Blue Grey #1F3B4D ΔE 0.049
- Marine #042E60 ΔE 0.050
- Midnight Green #073B4C ΔE 0.054
- Charcoal #264653 ΔE 0.058
Use #183C69 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.