#183D5D
Closest named color: Prussian Blue (#1D3557). oklch(35% 0.07 247.5), rgb(24, 61, 93).
Aa
White text reads best on this color (11.26:1).
About this color
#183D5D is a dark, moderately saturated blue. In OKLCH its lightness is 35%, its chroma 0.070 and its hue 248°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.025 away. White text reads best on it, at 11.26:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | moderately saturated (0.070) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.86:1 |
| White text | 11.26:1 |
Values
| HEX | #183D5D |
| RGB | rgb(24, 61, 93) |
| HSL | hsl(208, 59%, 23%) |
| OKLCH | oklch(35% 0.07 247.5) |
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 #183D5D | 11.26:1 | AAA | Lc -99.6 | Preferred for body text |
| Black text on #183D5D | 1.86:1 | Fails | Lc 8.1 | Not readable |
| #183D5D text on white | 11.26:1 | AAA | Lc 95.8 | Preferred for body text |
| #183D5D text on black | 1.86:1 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF4
oklch(93.6% 0.016 248)
-
Step 200
200
#CADBEC
oklch(88.4% 0.03 248.2)
-
Step 300
300
#A6C4E1
oklch(80.8% 0.052 247.6)
-
Step 400
400
#76A6D3
oklch(70.8% 0.084 247.5)
-
Step 500
500
#508FC7
oklch(63.2% 0.107 247.2)
-
Step 600
600
#3178B4
oklch(55.6% 0.117 247.4)
-
Step 700
700
#23659B
oklch(49.2% 0.109 247.3)
-
Step 800
800
#1F527D
oklch(42.6% 0.09 247.4)
-
Step 900
900 (this color)
#183D5D
oklch(35% 0.07 247.5)
-
Step 950
950
#13283B
oklch(26.9% 0.045 247.5)
#183D5D 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) | #2F3E5E | 0.027 |
| Deuteranopia (no green cones) | #25385C | 0.019 |
| Tritanopia (no blue cones) | #004548 | 0.054 |
| Achromatopsia (no color) | #3B3B3B | 0.070 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183D5D
#183D5D
oklch(35% 0.07 247.5)
- #523209
#523209
oklch(34.9% 0.07 67.2)
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 #183D5D, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.025
- Dark Blue Grey #1F3B4D ΔE 0.028
- Marine Blue #01386A ΔE 0.034
- Midnight Green #073B4C ΔE 0.034
- Dark Grey Blue #29465B ΔE 0.037
- Charcoal #264653 ΔE 0.042
- Twilight Blue #0A437A ΔE 0.050
- Marine #042E60 ΔE 0.053
Use #183D5D 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.