#243A73
Closest named color: Twilight Blue (#0A437A). oklch(36.3% 0.102 265.7), rgb(36, 58, 115).
Aa
White text reads best on this color (10.89:1).
About this color
#243A73 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.102 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.030 away. White text reads best on it, at 10.89:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.102) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.92:1 |
| White text | 10.89:1 |
Values
| HEX | #243A73 |
| RGB | rgb(36, 58, 115) |
| HSL | hsl(223, 52%, 30%) |
| OKLCH | oklch(36.3% 0.102 265.7) |
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 #243A73 | 10.89:1 | AAA | Lc -98.9 | Preferred for body text |
| Black text on #243A73 | 1.92:1 | Fails | Lc 8.9 | Not readable |
| #243A73 text on white | 10.89:1 | AAA | Lc 95.0 | Preferred for body text |
| #243A73 text on black | 1.92:1 | Fails | Lc -7.7 | 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
#7C9EED
oklch(70.7% 0.122 265.7)
-
Step 500
500
#5C84E7
oklch(63.2% 0.156 265.6)
-
Step 600
600
#436BD5
oklch(55.6% 0.169 265.6)
-
Step 700
700
#3558B9
oklch(49% 0.159 265.8)
-
Step 800
800
#2C4996
oklch(42.8% 0.131 265.6)
-
Step 900
900 (this color)
#243A73
oklch(36.3% 0.102 265.7)
-
Step 950
950
#172546
oklch(27.1% 0.064 265.1)
#243A73 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) | #1D4175 | 0.020 |
| Deuteranopia (no green cones) | #0C3972 | 0.022 |
| Tritanopia (no blue cones) | #004751 | 0.084 |
| Achromatopsia (no color) | #3D3D3D | 0.102 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243A73
#243A73
oklch(36.3% 0.102 265.7)
- #4F3A00
#4F3A00
oklch(36.2% 0.074 85.7)
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 #243A73, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.030
- Marine Blue #01386A ΔE 0.034
- Prussian Blue #1D3557 ΔE 0.051
- Cobalt #1E488F ΔE 0.057
- Marine #042E60 ΔE 0.059
- Dark Grey Blue #29465B ΔE 0.062
- Light Navy #155084 ΔE 0.066
- Dark Slate Blue #483D8B ΔE 0.069
Use #243A73 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.