#183A8A
Closest named color: Twilight Blue (#0A437A). oklch(37.7% 0.139 263.6), rgb(24, 58, 138).
Aa
White text reads best on this color (10.44:1).
About this color
#183A8A is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.139 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.039 away. White text reads best on it, at 10.44:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.139) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 2.01:1 |
| White text | 10.44:1 |
Values
| HEX | #183A8A |
| RGB | rgb(24, 58, 138) |
| HSL | hsl(222, 70%, 32%) |
| OKLCH | oklch(37.7% 0.139 263.6) |
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 #183A8A | 10.44:1 | AAA | Lc -97.8 | Preferred for body text |
| Black text on #183A8A | 2.01:1 | Fails | Lc 10.2 | Not readable |
| #183A8A text on white | 10.44:1 | AAA | Lc 93.7 | Preferred for body text |
| #183A8A text on black | 2.01:1 | Fails | Lc -8.8 | 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
#F1F6FF
oklch(97.2% 0.013 262.4)
-
Step 100
100
#E0EAFF
oklch(93.6% 0.03 265.3)
-
Step 200
200
#C6DAFF
oklch(88.5% 0.056 262.8)
-
Step 300
300
#A1C0FF
oklch(80.8% 0.096 264.1)
-
Step 400
400
#6E9DFF
oklch(70.6% 0.153 263.6)
-
Step 500
500
#4881FF
oklch(63.2% 0.197 263.5)
-
Step 600
600
#2562F8
oklch(55.5% 0.233 263.7)
-
Step 700
700
#1950D8
oklch(49.1% 0.216 263.6)
-
Step 800
800
#1743AF
oklch(42.8% 0.179 263.6)
-
Step 900
900 (this color)
#183A8A
oklch(37.7% 0.139 263.6)
-
Step 950
950
#0F2351
oklch(27.1% 0.088 263.8)
#183A8A 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) | #00458D | 0.030 |
| Deuteranopia (no green cones) | #003B88 | 0.014 |
| Tritanopia (no blue cones) | #004E5C | 0.108 |
| Achromatopsia (no color) | #404040 | 0.140 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183A8A
#183A8A
oklch(37.7% 0.139 263.6)
- #553D00
#553D00
oklch(37.7% 0.077 83.5)
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 #183A8A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.039
- Cobalt #1E488F ΔE 0.040
- Sapphire #2138AB ΔE 0.055
- Marine Blue #01386A ΔE 0.058
- Light Navy #155084 ΔE 0.065
- Dark Slate Blue #483D8B ΔE 0.065
- Blueberry #464196 ΔE 0.067
- Dusk Blue #26538D ΔE 0.074
Use #183A8A 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.