#243D87
Closest named color: Cobalt (#1E488F). oklch(38.6% 0.128 266.4), rgb(36, 61, 135).
Aa
White text reads best on this color (10.03:1).
About this color
#243D87 is a dark, moderately saturated blue. In OKLCH its lightness is 39%, its chroma 0.128 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.031 away. White text reads best on it, at 10.03:1.
| Hue family | Blues |
| Lightness | dark (39%) |
| Chroma | moderately saturated (0.128) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.09:1 |
| White text | 10.03:1 |
Values
| HEX | #243D87 |
| RGB | rgb(36, 61, 135) |
| HSL | hsl(225, 58%, 34%) |
| OKLCH | oklch(38.6% 0.128 266.4) |
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 #243D87 | 10.03:1 | AAA | Lc -97.1 | Preferred for body text |
| Black text on #243D87 | 2.09:1 | Fails | Lc 11.0 | Not readable |
| #243D87 text on white | 10.03:1 | AAA | Lc 92.9 | Preferred for body text |
| #243D87 text on black | 2.09:1 | Fails | Lc -9.6 | 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
#F1F5FE
oklch(97% 0.013 266.7)
-
Step 100
100
#E1EAFD
oklch(93.6% 0.028 265.4)
-
Step 200
200
#C9D9FD
oklch(88.5% 0.053 266.4)
-
Step 300
300
#A4BFFF
oklch(80.8% 0.096 266.6)
-
Step 400
400
#749CFF
oklch(70.8% 0.152 266)
-
Step 500
500
#527FFE
oklch(63.2% 0.195 266.2)
-
Step 600
600
#3964ED
oklch(55.6% 0.212 266.2)
-
Step 700
700
#2D51CF
oklch(49.1% 0.199 266.5)
-
Step 800
800
#2544A7
oklch(42.8% 0.163 266.2)
-
Step 900
900 (this color)
#243D87
oklch(38.6% 0.128 266.4)
-
Step 950
950
#14234D
oklch(27% 0.08 266.3)
#243D87 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) | #07478A | 0.030 |
| Deuteranopia (no green cones) | #003E86 | 0.024 |
| Tritanopia (no blue cones) | #004F5C | 0.102 |
| Achromatopsia (no color) | #424242 | 0.128 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243D87
#243D87
oklch(38.6% 0.128 266.4)
- #564000
#564000
oklch(38.5% 0.079 86.5)
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 #243D87, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.031
- Twilight Blue #0A437A ΔE 0.034
- Dark Slate Blue #483D8B ΔE 0.052
- Light Navy #155084 ΔE 0.055
- Blueberry #464196 ΔE 0.056
- Marine Blue #01386A ΔE 0.060
- Sapphire #2138AB ΔE 0.061
- Dusk Blue #26538D ΔE 0.063
Use #243D87 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.