#183F64
Closest named color: Marine Blue (#01386A). oklch(36% 0.078 249.9), rgb(24, 63, 100).
Aa
White text reads best on this color (10.85:1).
About this color
#183F64 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.078 and its hue 250°. Its hue sits on the cool side of the wheel. The nearest named color is Marine Blue (#01386A), ΔE 0.031 away. White text reads best on it, at 10.85:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.078) |
| Temperature | cool |
| Nearest name | Marine Blue (#01386A) |
| Black text | 1.93:1 |
| White text | 10.85:1 |
Values
| HEX | #183F64 |
| RGB | rgb(24, 63, 100) |
| HSL | hsl(209, 61%, 24%) |
| OKLCH | oklch(36% 0.078 249.9) |
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 #183F64 | 10.85:1 | AAA | Lc -98.8 | Preferred for body text |
| Black text on #183F64 | 1.93:1 | Fails | Lc 9.0 | Not readable |
| #183F64 text on white | 10.85:1 | AAA | Lc 94.9 | Preferred for body text |
| #183F64 text on black | 1.93:1 | Fails | Lc -7.7 | 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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF5
oklch(93.6% 0.017 250.8)
-
Step 200
200
#CADBEE
oklch(88.5% 0.032 251.1)
-
Step 300
300
#A5C4E6
oklch(80.9% 0.059 250.9)
-
Step 400
400
#73A5D9
oklch(70.7% 0.093 250.2)
-
Step 500
500
#4C8ECF
oklch(63.2% 0.119 249.9)
-
Step 600
600
#2C77BC
oklch(55.7% 0.13 249.9)
-
Step 700
700
#1D63A2
oklch(49% 0.122 250.1)
-
Step 800
800
#1B5183
oklch(42.6% 0.1 250.1)
-
Step 900
900 (this color)
#183F64
oklch(36% 0.078 249.9)
-
Step 950
950
#12283E
oklch(27.1% 0.05 250.2)
#183F64 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) | #2E4166 | 0.026 |
| Deuteranopia (no green cones) | #233A63 | 0.017 |
| Tritanopia (no blue cones) | #00484C | 0.060 |
| Achromatopsia (no color) | #3D3D3D | 0.078 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183F64
#183F64
oklch(36% 0.078 249.9)
- #573400
#573400
oklch(36% 0.078 69)
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 #183F64, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Marine Blue #01386A ΔE 0.031
- Prussian Blue #1D3557 ΔE 0.035
- Dark Grey Blue #29465B ΔE 0.036
- Twilight Blue #0A437A ΔE 0.038
- Dark Blue Grey #1F3B4D ΔE 0.040
- Charcoal #264653 ΔE 0.045
- Midnight Green #073B4C ΔE 0.046
- Marine #042E60 ΔE 0.058
Use #183F64 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.