#183F6A
Closest named color: Twilight Blue (#0A437A). oklch(36.4% 0.086 253.2), rgb(24, 63, 106).
Aa
White text reads best on this color (10.72:1).
About this color
#183F6A is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.086 and its hue 253°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.028 away. White text reads best on it, at 10.72:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.086) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.95:1 |
| White text | 10.72:1 |
Values
| HEX | #183F6A |
| RGB | rgb(24, 63, 106) |
| HSL | hsl(211, 63%, 25%) |
| OKLCH | oklch(36.4% 0.086 253.2) |
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 #183F6A | 10.72:1 | AAA | Lc -98.5 | Preferred for body text |
| Black text on #183F6A | 1.95:1 | Fails | Lc 9.3 | Not readable |
| #183F6A text on white | 10.72:1 | AAA | Lc 94.6 | Preferred for body text |
| #183F6A text on black | 1.95:1 | Fails | Lc -8.0 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E1EBF6
oklch(93.6% 0.018 250.6)
-
Step 200
200
#C9DBF1
oklch(88.5% 0.036 253.5)
-
Step 300
300
#A4C4EA
oklch(81% 0.064 253)
-
Step 400
400
#71A4E0
oklch(70.7% 0.104 253.2)
-
Step 500
500
#4A8CD7
oklch(63.1% 0.132 253.2)
-
Step 600
600
#2974C5
oklch(55.5% 0.145 253.4)
-
Step 700
700
#1B61AA
oklch(49% 0.135 253.3)
-
Step 800
800
#1A508A
oklch(42.8% 0.111 253.3)
-
Step 900
900 (this color)
#183F6A
oklch(36.4% 0.086 253.2)
-
Step 950
950
#112740
oklch(26.9% 0.055 253.1)
#183F6A 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) | #2B426C | 0.024 |
| Deuteranopia (no green cones) | #1E3A69 | 0.015 |
| Tritanopia (no blue cones) | #00494F | 0.066 |
| Achromatopsia (no color) | #3E3E3E | 0.086 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183F6A
#183F6A
oklch(36.4% 0.086 253.2)
- #563600
#563600
oklch(36.2% 0.077 72.7)
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 #183F6A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.028
- Marine Blue #01386A ΔE 0.028
- Prussian Blue #1D3557 ΔE 0.041
- Dark Grey Blue #29465B ΔE 0.043
- Dark Blue Grey #1F3B4D ΔE 0.050
- Charcoal #264653 ΔE 0.053
- Midnight Green #073B4C ΔE 0.056
- Marine #042E60 ΔE 0.058
Use #183F6A 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.