#183D5C
Closest named color: Prussian Blue (#1D3557). oklch(34.9% 0.069 246.8), rgb(24, 61, 92).
Aa
White text reads best on this color (11.28:1).
About this color
#183D5C is a dark, muted blue. In OKLCH its lightness is 35%, its chroma 0.069 and its hue 247°. 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 11.28:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | muted (0.069) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.86:1 |
| White text | 11.28:1 |
Values
| HEX | #183D5C |
| RGB | rgb(24, 61, 92) |
| HSL | hsl(207, 59%, 23%) |
| OKLCH | oklch(34.9% 0.069 246.8) |
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 #183D5C | 11.28:1 | AAA | Lc -99.6 | Preferred for body text |
| Black text on #183D5C | 1.86:1 | Fails | Lc 8.1 | Not readable |
| #183D5C text on white | 11.28:1 | AAA | Lc 95.8 | Preferred for body text |
| #183D5C 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
#CBDBEB
oklch(88.4% 0.028 248.1)
-
Step 300
300
#A6C4E1
oklch(80.8% 0.052 247.6)
-
Step 400
400
#76A6D2
oklch(70.8% 0.083 246.9)
-
Step 500
500
#508FC6
oklch(63.1% 0.106 246.8)
-
Step 600
600
#3278B2
oklch(55.6% 0.114 246.9)
-
Step 700
700
#236599
oklch(49.1% 0.106 246.3)
-
Step 800
800
#1F527C
oklch(42.6% 0.088 246.8)
-
Step 900
900 (this color)
#183D5C
oklch(34.9% 0.069 246.8)
-
Step 950
950
#13283B
oklch(26.9% 0.045 247.5)
#183D5C 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) | #2F3E5D | 0.027 |
| Deuteranopia (no green cones) | #26385B | 0.020 |
| Tritanopia (no blue cones) | #004448 | 0.050 |
| Achromatopsia (no color) | #3B3B3B | 0.069 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183D5C
#183D5C
oklch(34.9% 0.069 246.8)
- #52320B
#52320B
oklch(34.9% 0.069 66.4)
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 #183D5C, 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 0.026
- Midnight Green #073B4C ΔE 0.032
- Marine Blue #01386A ΔE 0.035
- Dark Grey Blue #29465B ΔE 0.037
- Charcoal #264653 ΔE 0.041
- Twilight Blue #0A437A ΔE 0.052
- Gunmetal #293241 ΔE 0.053
Use #183D5C 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.