#243A71
Closest named color: Twilight Blue (#0A437A). oklch(36.2% 0.099 265.4), rgb(36, 58, 113).
Aa
White text reads best on this color (10.94:1).
About this color
#243A71 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.099 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.031 away. White text reads best on it, at 10.94:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.099) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.91:1 |
| White text | 10.94:1 |
Values
| HEX | #243A71 |
| RGB | rgb(36, 58, 113) |
| HSL | hsl(223, 52%, 29%) |
| OKLCH | oklch(36.2% 0.099 265.4) |
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 #243A71 | 10.94:1 | AAA | Lc -99.0 | Preferred for body text |
| Black text on #243A71 | 1.91:1 | Fails | Lc 8.8 | Not readable |
| #243A71 text on white | 10.94:1 | AAA | Lc 95.1 | Preferred for body text |
| #243A71 text on black | 1.91:1 | Fails | Lc -7.5 | 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
#F2F5FC
oklch(97% 0.01 267.4)
-
Step 100
100
#E3EAF9
oklch(93.6% 0.022 265.8)
-
Step 200
200
#CCD9F5
oklch(88.4% 0.041 265.7)
-
Step 300
300
#AAC0F1
oklch(80.8% 0.074 265.9)
-
Step 400
400
#7D9EEB
oklch(70.6% 0.119 265.8)
-
Step 500
500
#5D84E4
oklch(63% 0.151 265.6)
-
Step 600
600
#446CD2
oklch(55.6% 0.164 265.3)
-
Step 700
700
#3659B6
oklch(49% 0.153 265.5)
-
Step 800
800
#2D4994
oklch(42.7% 0.128 265.8)
-
Step 900
900 (this color)
#243A71
oklch(36.2% 0.099 265.4)
-
Step 950
950
#172545
oklch(27% 0.063 264.7)
#243A71 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) | #1F4073 | 0.017 |
| Deuteranopia (no green cones) | #103970 | 0.020 |
| Tritanopia (no blue cones) | #004750 | 0.083 |
| Achromatopsia (no color) | #3D3D3D | 0.099 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243A71
#243A71
oklch(36.2% 0.099 265.4)
- #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 #243A71, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.031
- Marine Blue #01386A ΔE 0.032
- Prussian Blue #1D3557 ΔE 0.048
- Marine #042E60 ΔE 0.057
- Dark Grey Blue #29465B ΔE 0.060
- Cobalt #1E488F ΔE 0.060
- Dark Blue Grey #1F3B4D ΔE 0.065
- Light Navy #155084 ΔE 0.067
Use #243A71 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.