#243C9F
Closest named color: Sapphire (#2138AB). oklch(40.4% 0.163 267.7), rgb(36, 60, 159).
Aa
White text reads best on this color (9.45:1).
About this color
#243C9F is a dark, vivid blue. In OKLCH its lightness is 40%, its chroma 0.163 and its hue 268°. Its hue sits on the cool side of the wheel. The nearest named color is Sapphire (#2138AB), ΔE 0.022 away. White text reads best on it, at 9.45:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | vivid (0.163) |
| Temperature | cool |
| Nearest name | Sapphire (#2138AB) |
| Black text | 2.22:1 |
| White text | 9.45:1 |
Values
| HEX | #243C9F |
| RGB | rgb(36, 60, 159) |
| HSL | hsl(228, 63%, 38%) |
| OKLCH | oklch(40.4% 0.163 267.7) |
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 #243C9F | 9.45:1 | AAA | Lc -95.6 | Preferred for body text |
| Black text on #243C9F | 2.22:1 | Fails | Lc 12.7 | Not readable |
| #243C9F text on white | 9.45:1 | AAA | Lc 91.3 | Preferred for body text |
| #243C9F text on black | 2.22:1 | Fails | Lc -11.1 | 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 800.
-
Step 50
50
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E2EAFD
oklch(93.7% 0.027 267.5)
-
Step 200
200
#CAD9FD
oklch(88.6% 0.052 267.4)
-
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
#577EFD
oklch(63.1% 0.194 267.7)
-
Step 600
600
#3F63ED
oklch(55.7% 0.212 267.7)
-
Step 700
700
#3251CE
oklch(49.2% 0.196 267.7)
-
Step 800
800 (this color)
#243C9F
oklch(40.4% 0.163 267.7)
-
Step 900
900
#253A84
oklch(37.7% 0.127 267.9)
-
Step 950
950
#15234D
oklch(27% 0.08 267.1)
#243C9F 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) | #004CA2 | 0.041 |
| Deuteranopia (no green cones) | #00409D | 0.023 |
| Tritanopia (no blue cones) | #005567 | 0.128 |
| Achromatopsia (no color) | #464646 | 0.163 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243C9F
#243C9F
oklch(40.4% 0.163 267.7)
- #5C4500
#5C4500
oklch(40.4% 0.083 86.9)
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 #243C9F, closest first.
No curated palette has a color within ΔE 0.04 of #243C9F.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Sapphire #2138AB ΔE 0.022
- Cobalt #1E488F ΔE 0.042
- Blueberry #464196 ΔE 0.051
- Dark Slate Blue #483D8B ΔE 0.060
- Blue Blue #2242C7 ΔE 0.066
- Indigo Blue #3A18B1 ΔE 0.067
- Twilight Blue #0A437A ΔE 0.069
- Dusk Blue #26538D ΔE 0.072
Use #243C9F 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.