#183D5F
Closest named color: Prussian Blue (#1D3557). oklch(35.1% 0.073 249), rgb(24, 61, 95).
Aa
White text reads best on this color (11.22:1).
About this color
#183D5F is a dark, moderately saturated blue. In OKLCH its lightness is 35%, its chroma 0.073 and its hue 249°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.026 away. White text reads best on it, at 11.22:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | moderately saturated (0.073) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.87:1 |
| White text | 11.22:1 |
Values
| HEX | #183D5F |
| RGB | rgb(24, 61, 95) |
| HSL | hsl(209, 60%, 23%) |
| OKLCH | oklch(35.1% 0.073 249) |
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 #183D5F | 11.22:1 | AAA | Lc -99.5 | Preferred for body text |
| Black text on #183D5F | 1.87:1 | Fails | Lc 8.2 | Not readable |
| #183D5F text on white | 11.22:1 | AAA | Lc 95.7 | Preferred for body text |
| #183D5F text on black | 1.87:1 | 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
#CADBED
oklch(88.4% 0.031 249.7)
-
Step 300
300
#A6C4E3
oklch(80.9% 0.055 249.4)
-
Step 400
400
#75A5D5
oklch(70.6% 0.088 249.2)
-
Step 500
500
#4F8ECA
oklch(63.1% 0.112 249)
-
Step 600
600
#3177B7
oklch(55.6% 0.122 249.3)
-
Step 700
700
#22649E
oklch(49.1% 0.114 249)
-
Step 800
800
#1F5280
oklch(42.8% 0.094 249)
-
Step 900
900 (this color)
#183D5F
oklch(35.1% 0.073 249)
-
Step 950
950
#13283C
oklch(27% 0.046 248.8)
#183D5F 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) | #2E3F60 | 0.027 |
| Deuteranopia (no green cones) | #24385E | 0.018 |
| Tritanopia (no blue cones) | #004549 | 0.055 |
| Achromatopsia (no color) | #3B3B3B | 0.073 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183D5F
#183D5F
oklch(35.1% 0.073 249)
- #533305
#533305
oklch(35.2% 0.073 69.4)
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 #183D5F, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.026
- Dark Blue Grey #1F3B4D ΔE 0.031
- Marine Blue #01386A ΔE 0.031
- Midnight Green #073B4C ΔE 0.037
- Dark Grey Blue #29465B ΔE 0.038
- Charcoal #264653 ΔE 0.044
- Twilight Blue #0A437A ΔE 0.047
- Marine #042E60 ΔE 0.053
Use #183D5F 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.