#243A8B
Closest named color: Cobalt (#1E488F). oklch(38.3% 0.137 267.8), rgb(36, 58, 139).
Aa
White text reads best on this color (10.22:1).
About this color
#243A8B is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.137 and its hue 268°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.037 away. White text reads best on it, at 10.22:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.137) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.05:1 |
| White text | 10.22:1 |
Values
| HEX | #243A8B |
| RGB | rgb(36, 58, 139) |
| HSL | hsl(227, 59%, 34%) |
| OKLCH | oklch(38.3% 0.137 267.8) |
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 #243A8B | 10.22:1 | AAA | Lc -97.4 | Preferred for body text |
| Black text on #243A8B | 2.05:1 | Fails | Lc 10.6 | Not readable |
| #243A8B text on white | 10.22:1 | AAA | Lc 93.3 | Preferred for body text |
| #243A8B text on black | 2.05:1 | Fails | Lc -9.2 | 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
#F1F5FF
oklch(97% 0.014 268.5)
-
Step 100
100
#E1EAFF
oklch(93.7% 0.03 267.2)
-
Step 200
200
#C9D9FF
oklch(88.6% 0.055 267.2)
-
Step 300
300
#A6BFFF
oklch(80.9% 0.095 267.8)
-
Step 400
400
#779BFF
oklch(70.7% 0.152 267.5)
-
Step 500
500
#567DFF
oklch(63% 0.198 267.8)
-
Step 600
600
#3C5FF6
oklch(55.6% 0.228 267.9)
-
Step 700
700
#2F4DD7
oklch(49.1% 0.213 267.7)
-
Step 800
800
#2740AD
oklch(42.6% 0.176 267.9)
-
Step 900
900 (this color)
#243A8B
oklch(38.3% 0.137 267.8)
-
Step 950
950
#142250
oklch(27% 0.086 267.5)
#243A8B 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) | #00468E | 0.035 |
| Deuteranopia (no green cones) | #003C89 | 0.025 |
| Tritanopia (no blue cones) | #004E5C | 0.111 |
| Achromatopsia (no color) | #414141 | 0.138 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243A8B
#243A8B
oklch(38.3% 0.137 267.8)
- #554000
#554000
oklch(38.4% 0.078 87.5)
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 #243A8B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.037
- Twilight Blue #0A437A ΔE 0.043
- Sapphire #2138AB ΔE 0.053
- Dark Slate Blue #483D8B ΔE 0.054
- Blueberry #464196 ΔE 0.056
- Light Navy #155084 ΔE 0.064
- Marine Blue #01386A ΔE 0.065
- Dusk Blue #26538D ΔE 0.070
Use #243A8B 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.