#243C75
Closest named color: Twilight Blue (#0A437A). oklch(37% 0.102 264.7), rgb(36, 60, 117).
Aa
White text reads best on this color (10.61:1).
About this color
#243C75 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.102 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.025 away. White text reads best on it, at 10.61:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.102) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.97:1 |
| White text | 10.61:1 |
Values
| HEX | #243C75 |
| RGB | rgb(36, 60, 117) |
| HSL | hsl(222, 53%, 30%) |
| OKLCH | oklch(37% 0.102 264.7) |
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 #243C75 | 10.61:1 | AAA | Lc -98.3 | Preferred for body text |
| Black text on #243C75 | 1.97:1 | Fails | Lc 9.6 | Not readable |
| #243C75 text on white | 10.61:1 | AAA | Lc 94.4 | Preferred for body text |
| #243C75 text on black | 1.97:1 | Fails | Lc -8.2 | 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
#F2F5FD
oklch(97% 0.011 269.6)
-
Step 100
100
#E3EAF9
oklch(93.6% 0.022 265.8)
-
Step 200
200
#CBD9F6
oklch(88.4% 0.043 265)
-
Step 300
300
#A8C1F3
oklch(81% 0.076 264)
-
Step 400
400
#7A9FED
oklch(70.8% 0.122 264.2)
-
Step 500
500
#5984E7
oklch(63% 0.157 264.6)
-
Step 600
600
#406BD6
oklch(55.5% 0.171 264.9)
-
Step 700
700
#3259B9
oklch(49.1% 0.158 264.6)
-
Step 800
800
#2A4996
oklch(42.7% 0.132 264.8)
-
Step 900
900 (this color)
#243C75
oklch(37% 0.102 264.7)
-
Step 950
950
#162546
oklch(27.1% 0.065 264.1)
#243C75 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) | #1F4277 | 0.017 |
| Deuteranopia (no green cones) | #0F3B74 | 0.020 |
| Tritanopia (no blue cones) | #004952 | 0.085 |
| Achromatopsia (no color) | #3E3E3E | 0.102 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243C75
#243C75
oklch(37% 0.102 264.7)
- #523C00
#523C00
oklch(37.1% 0.076 85.3)
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 #243C75, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.025
- Marine Blue #01386A ΔE 0.037
- Cobalt #1E488F ΔE 0.052
- Prussian Blue #1D3557 ΔE 0.055
- Light Navy #155084 ΔE 0.059
- Dark Grey Blue #29465B ΔE 0.061
- Marine #042E60 ΔE 0.065
- Dark Slate Blue #483D8B ΔE 0.065
Use #243C75 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.