#243D78
Closest named color: Twilight Blue (#0A437A). oklch(37.4% 0.105 264.6), rgb(36, 61, 120).
Aa
White text reads best on this color (10.42:1).
About this color
#243D78 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.105 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.023 away. White text reads best on it, at 10.42:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.105) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 2.01:1 |
| White text | 10.42:1 |
Values
| HEX | #243D78 |
| RGB | rgb(36, 61, 120) |
| HSL | hsl(222, 54%, 31%) |
| OKLCH | oklch(37.4% 0.105 264.6) |
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 #243D78 | 10.42:1 | AAA | Lc -98.0 | Preferred for body text |
| Black text on #243D78 | 2.01:1 | Fails | Lc 10.0 | Not readable |
| #243D78 text on white | 10.42:1 | AAA | Lc 93.9 | Preferred for body text |
| #243D78 text on black | 2.01:1 | Fails | Lc -8.6 | 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
#F2F6FD
oklch(97.2% 0.01 261.8)
-
Step 100
100
#E2EAFA
oklch(93.6% 0.023 264.5)
-
Step 200
200
#CBD9F7
oklch(88.4% 0.044 265.6)
-
Step 300
300
#A7C1F5
oklch(81% 0.079 264)
-
Step 400
400
#799EEF
oklch(70.6% 0.126 264.7)
-
Step 500
500
#5784EA
oklch(63.1% 0.161 264.4)
-
Step 600
600
#3E6BD9
oklch(55.7% 0.176 264.6)
-
Step 700
700
#3058BC
oklch(49% 0.164 264.6)
-
Step 800
800
#284998
oklch(42.7% 0.135 264.3)
-
Step 900
900 (this color)
#243D78
oklch(37.4% 0.105 264.6)
-
Step 950
950
#162547
oklch(27.1% 0.066 264.5)
#243D78 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) | #1E447A | 0.020 |
| Deuteranopia (no green cones) | #0C3C77 | 0.021 |
| Tritanopia (no blue cones) | #004B54 | 0.088 |
| Achromatopsia (no color) | #404040 | 0.105 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243D78
#243D78
oklch(37.4% 0.105 264.6)
- #543D00
#543D00
oklch(37.5% 0.077 84.5)
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 #243D78, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.023
- Marine Blue #01386A ΔE 0.041
- Cobalt #1E488F ΔE 0.046
- Light Navy #155084 ΔE 0.056
- Prussian Blue #1D3557 ΔE 0.061
- Dark Slate Blue #483D8B ΔE 0.062
- Dark Grey Blue #29465B ΔE 0.063
- Deep Sea Blue #015482 ΔE 0.067
Use #243D78 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.