#183E78
Closest named color: Twilight Blue (#0A437A). oklch(37.1% 0.108 258.9), rgb(24, 62, 120).
Aa
White text reads best on this color (10.50:1).
About this color
#183E78 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.108 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.015 away. White text reads best on it, at 10.50:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.108) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.99:1 |
| White text | 10.50:1 |
Values
| HEX | #183E78 |
| RGB | rgb(24, 62, 120) |
| HSL | hsl(216, 67%, 28%) |
| OKLCH | oklch(37.1% 0.108 258.9) |
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 #183E78 | 10.50:1 | AAA | Lc -98.0 | Preferred for body text |
| Black text on #183E78 | 1.99:1 | Fails | Lc 9.9 | Not readable |
| #183E78 text on white | 10.50:1 | AAA | Lc 94.0 | Preferred for body text |
| #183E78 text on black | 1.99:1 | Fails | Lc -8.5 | 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
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E1EBFA
oklch(93.7% 0.023 258.4)
-
Step 200
200
#C8DBF8
oklch(88.6% 0.045 258.8)
-
Step 300
300
#A1C2F5
oklch(80.8% 0.081 259)
-
Step 400
400
#6EA1F1
oklch(70.7% 0.13 259.1)
-
Step 500
500
#4687EC
oklch(63.1% 0.166 259)
-
Step 600
600
#266EDA
oklch(55.5% 0.18 258.9)
-
Step 700
700
#185BBD
oklch(49% 0.168 258.9)
-
Step 800
800
#174B99
oklch(42.6% 0.139 259)
-
Step 900
900 (this color)
#183E78
oklch(37.1% 0.108 258.9)
-
Step 950
950
#102647
oklch(27% 0.068 258.4)
#183E78 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) | #1F447A | 0.020 |
| Deuteranopia (no green cones) | #073B77 | 0.015 |
| Tritanopia (no blue cones) | #004C55 | 0.084 |
| Achromatopsia (no color) | #3F3F3F | 0.108 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183E78
#183E78
oklch(37.1% 0.108 258.9)
- #563A00
#563A00
oklch(37.1% 0.077 78.3)
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 #183E78, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.015
- Marine Blue #01386A ΔE 0.034
- Cobalt #1E488F ΔE 0.047
- Light Navy #155084 ΔE 0.054
- Prussian Blue #1D3557 ΔE 0.059
- Dark Grey Blue #29465B ΔE 0.063
- Deep Sea Blue #015482 ΔE 0.064
- Marine #042E60 ΔE 0.065
Use #183E78 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.