#243D7B
Closest named color: Twilight Blue (#0A437A). oklch(37.6% 0.11 265), rgb(36, 61, 123).
Aa
White text reads best on this color (10.35:1).
About this color
#243D7B is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.110 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.024 away. White text reads best on it, at 10.35:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.110) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 2.02:1 |
| White text | 10.35:1 |
Values
| HEX | #243D7B |
| RGB | rgb(36, 61, 123) |
| HSL | hsl(223, 55%, 31%) |
| OKLCH | oklch(37.6% 0.11 265) |
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 #243D7B | 10.35:1 | AAA | Lc -97.8 | Preferred for body text |
| Black text on #243D7B | 2.02:1 | Fails | Lc 10.2 | Not readable |
| #243D7B text on white | 10.35:1 | AAA | Lc 93.7 | Preferred for body text |
| #243D7B text on black | 2.02:1 | 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
#F2F5FD
oklch(97% 0.011 269.6)
-
Step 100
100
#E2EAFA
oklch(93.6% 0.023 264.5)
-
Step 200
200
#CAD9F8
oklch(88.4% 0.046 264.9)
-
Step 300
300
#A7C0F7
oklch(80.9% 0.083 265.6)
-
Step 400
400
#789EF3
oklch(70.8% 0.132 264.9)
-
Step 500
500
#5683EE
oklch(63.1% 0.168 264.8)
-
Step 600
600
#3D6ADD
oklch(55.7% 0.183 264.9)
-
Step 700
700
#3057C0
oklch(49.1% 0.171 265.2)
-
Step 800
800
#28489B
oklch(42.7% 0.141 265)
-
Step 900
900 (this color)
#243D7B
oklch(37.6% 0.11 265)
-
Step 950
950
#152448
oklch(26.9% 0.07 265)
#243D7B 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) | #1B447D | 0.020 |
| Deuteranopia (no green cones) | #053C7A | 0.024 |
| Tritanopia (no blue cones) | #004B56 | 0.089 |
| Achromatopsia (no color) | #404040 | 0.110 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243D7B
#243D7B
oklch(37.6% 0.11 265)
- #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 #243D7B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.024
- Cobalt #1E488F ΔE 0.042
- Marine Blue #01386A ΔE 0.044
- Light Navy #155084 ΔE 0.055
- Dark Slate Blue #483D8B ΔE 0.059
- Prussian Blue #1D3557 ΔE 0.065
- Deep Sea Blue #015482 ΔE 0.066
- Dark Grey Blue #29465B ΔE 0.067
Use #243D7B 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.