#183D8A
Closest named color: Cobalt (#1E488F). oklch(38.3% 0.136 262.6), rgb(24, 61, 138).
Aa
White text reads best on this color (10.12:1).
About this color
#183D8A is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.136 and its hue 263°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.032 away. White text reads best on it, at 10.12:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.136) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.07:1 |
| White text | 10.12:1 |
Values
| HEX | #183D8A |
| RGB | rgb(24, 61, 138) |
| HSL | hsl(221, 70%, 32%) |
| OKLCH | oklch(38.3% 0.136 262.6) |
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 #183D8A | 10.12:1 | AAA | Lc -97.1 | Preferred for body text |
| Black text on #183D8A | 2.07:1 | Fails | Lc 10.9 | Not readable |
| #183D8A text on white | 10.12:1 | AAA | Lc 93.0 | Preferred for body text |
| #183D8A text on black | 2.07:1 | Fails | Lc -9.5 | 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
#DFEAFE
oklch(93.5% 0.03 262.5)
-
Step 200
200
#C6DAFF
oklch(88.5% 0.056 262.8)
-
Step 300
300
#A0C1FF
oklch(80.9% 0.095 262.7)
-
Step 400
400
#6C9EFF
oklch(70.7% 0.152 262.5)
-
Step 500
500
#4481FF
oklch(63% 0.198 262.7)
-
Step 600
600
#2165F4
oklch(55.7% 0.225 262.5)
-
Step 700
700
#1452D5
oklch(49.1% 0.21 262.6)
-
Step 800
800
#1344AC
oklch(42.6% 0.174 262.6)
-
Step 900
900 (this color)
#183D8A
oklch(38.3% 0.136 262.6)
-
Step 950
950
#0E2350
oklch(26.9% 0.087 263)
#183D8A 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) | #00478D | 0.027 |
| Deuteranopia (no green cones) | #003D88 | 0.014 |
| Tritanopia (no blue cones) | #00505D | 0.105 |
| Achromatopsia (no color) | #414141 | 0.136 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183D8A
#183D8A
oklch(38.3% 0.136 262.6)
- #583E00
#583E00
oklch(38.3% 0.079 81.8)
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 #183D8A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.032
- Twilight Blue #0A437A ΔE 0.034
- Sapphire #2138AB ΔE 0.056
- Light Navy #155084 ΔE 0.057
- Marine Blue #01386A ΔE 0.059
- Dark Slate Blue #483D8B ΔE 0.062
- Blueberry #464196 ΔE 0.064
- Dusk Blue #26538D ΔE 0.066
Use #183D8A 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.