#243C84
Closest named color: Twilight Blue (#0A437A). oklch(38.1% 0.125 266.6), rgb(36, 60, 132).
Aa
White text reads best on this color (10.22:1).
About this color
#243C84 is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.125 and its hue 267°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.032 away. White text reads best on it, at 10.22:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.125) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 2.05:1 |
| White text | 10.22:1 |
Values
| HEX | #243C84 |
| RGB | rgb(36, 60, 132) |
| HSL | hsl(225, 57%, 33%) |
| OKLCH | oklch(38.1% 0.125 266.6) |
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 #243C84 | 10.22:1 | AAA | Lc -97.5 | Preferred for body text |
| Black text on #243C84 | 2.05:1 | Fails | Lc 10.6 | Not readable |
| #243C84 text on white | 10.22:1 | AAA | Lc 93.4 | Preferred for body text |
| #243C84 text on black | 2.05:1 | Fails | Lc -9.1 | 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
#F1F5FE
oklch(97% 0.013 266.7)
-
Step 100
100
#E2EAFD
oklch(93.7% 0.027 267.5)
-
Step 200
200
#C9D9FD
oklch(88.5% 0.053 266.4)
-
Step 300
300
#A5BFFE
oklch(80.8% 0.094 267)
-
Step 400
400
#769CFD
oklch(70.8% 0.148 266.5)
-
Step 500
500
#547FFB
oklch(63% 0.191 266.5)
-
Step 600
600
#3B64EB
oklch(55.5% 0.209 266.5)
-
Step 700
700
#2F52CC
oklch(49.1% 0.193 266.7)
-
Step 800
800
#2744A5
oklch(42.7% 0.16 266.7)
-
Step 900
900 (this color)
#243C84
oklch(38.1% 0.125 266.6)
-
Step 950
950
#15234D
oklch(27% 0.08 267.1)
#243C84 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) | #0A4687 | 0.030 |
| Deuteranopia (no green cones) | #003D83 | 0.025 |
| Tritanopia (no blue cones) | #004D5A | 0.100 |
| Achromatopsia (no color) | #414141 | 0.125 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243C84
#243C84
oklch(38.1% 0.125 266.6)
- #553F00
#553F00
oklch(38.1% 0.078 86.2)
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 #243C84, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.032
- Cobalt #1E488F ΔE 0.036
- Dark Slate Blue #483D8B ΔE 0.054
- Marine Blue #01386A ΔE 0.055
- Light Navy #155084 ΔE 0.057
- Blueberry #464196 ΔE 0.059
- Sapphire #2138AB ΔE 0.065
- Dusk Blue #26538D ΔE 0.066
Use #243C84 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.