#243B74
Closest named color: Twilight Blue (#0A437A). oklch(36.6% 0.102 265.2), rgb(36, 59, 116).
Aa
White text reads best on this color (10.75:1).
About this color
#243B74 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.102 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.028 away. White text reads best on it, at 10.75:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.102) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.95:1 |
| White text | 10.75:1 |
Values
| HEX | #243B74 |
| RGB | rgb(36, 59, 116) |
| HSL | hsl(223, 53%, 30%) |
| OKLCH | oklch(36.6% 0.102 265.2) |
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 #243B74 | 10.75:1 | AAA | Lc -98.6 | Preferred for body text |
| Black text on #243B74 | 1.95:1 | Fails | Lc 9.2 | Not readable |
| #243B74 text on white | 10.75:1 | AAA | Lc 94.7 | Preferred for body text |
| #243B74 text on black | 1.95:1 | Fails | Lc -7.9 | 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
#E3EAF9
oklch(93.6% 0.022 265.8)
-
Step 200
200
#CCD9F6
oklch(88.5% 0.042 266.3)
-
Step 300
300
#A9C0F3
oklch(80.8% 0.077 265.8)
-
Step 400
400
#7B9EED
oklch(70.6% 0.123 265.2)
-
Step 500
500
#5B84E7
oklch(63.1% 0.156 265.3)
-
Step 600
600
#426BD5
oklch(55.6% 0.169 265.3)
-
Step 700
700
#3459B9
oklch(49.2% 0.158 265.2)
-
Step 800
800
#2B4996
oklch(42.7% 0.131 265.2)
-
Step 900
900 (this color)
#243B74
oklch(36.6% 0.102 265.2)
-
Step 950
950
#172546
oklch(27.1% 0.064 265.1)
#243B74 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) | #1E4276 | 0.020 |
| Deuteranopia (no green cones) | #0E3A73 | 0.021 |
| Tritanopia (no blue cones) | #004852 | 0.083 |
| Achromatopsia (no color) | #3E3E3E | 0.102 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243B74
#243B74
oklch(36.6% 0.102 265.2)
- #513B00
#513B00
oklch(36.7% 0.075 84.9)
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 #243B74, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.028
- Marine Blue #01386A ΔE 0.035
- Prussian Blue #1D3557 ΔE 0.053
- Cobalt #1E488F ΔE 0.054
- Dark Grey Blue #29465B ΔE 0.061
- Marine #042E60 ΔE 0.062
- Light Navy #155084 ΔE 0.063
- Dark Slate Blue #483D8B ΔE 0.067
Use #243B74 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.