#183F65
Closest named color: Marine Blue (#01386A). oklch(36% 0.079 250.5), rgb(24, 63, 101).
Aa
White text reads best on this color (10.83:1).
About this color
#183F65 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.079 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 10.83:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.079) |
| Temperature | cool |
| Nearest name | Marine Blue (#01386A) |
| Black text | 1.93:1 |
| White text | 10.83:1 |
Values
| HEX | #183F65 |
| RGB | rgb(24, 63, 101) |
| HSL | hsl(210, 62%, 25%) |
| OKLCH | oklch(36% 0.079 250.5) |
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 #183F65 | 10.83:1 | AAA | Lc -98.8 | Preferred for body text |
| Black text on #183F65 | 1.93:1 | Fails | Lc 9.1 | Not readable |
| #183F65 text on white | 10.83:1 | AAA | Lc 94.8 | Preferred for body text |
| #183F65 text on black | 1.93:1 | Fails | Lc -7.8 | 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
#C9DBEF
oklch(88.4% 0.034 251)
-
Step 300
300
#A4C4E6
oklch(80.8% 0.059 250.1)
-
Step 400
400
#72A5DA
oklch(70.7% 0.095 250.2)
-
Step 500
500
#4B8DD0
oklch(63% 0.122 250.7)
-
Step 600
600
#2B76BD
oklch(55.5% 0.132 250.6)
-
Step 700
700
#1D63A3
oklch(49.1% 0.123 250.5)
-
Step 800
800
#1B5184
oklch(42.7% 0.102 250.5)
-
Step 900
900 (this color)
#183F65
oklch(36% 0.079 250.5)
-
Step 950
950
#12283E
oklch(27.1% 0.05 250.2)
#183F65 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) | #2E4167 | 0.026 |
| Deuteranopia (no green cones) | #233A64 | 0.017 |
| Tritanopia (no blue cones) | #00484D | 0.060 |
| Achromatopsia (no color) | #3D3D3D | 0.079 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183F65
#183F65
oklch(36% 0.079 250.5)
- #563500
#563500
oklch(36% 0.077 71.3)
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 #183F65, 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 0.036
- Twilight Blue #0A437A ΔE 0.036
- Dark Grey Blue #29465B ΔE 0.037
- Dark Blue Grey #1F3B4D ΔE 0.041
- Charcoal #264653 ΔE 0.046
- Midnight Green #073B4C ΔE 0.047
- Marine #042E60 ΔE 0.058
Use #183F65 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.