#243C77
Closest named color: Twilight Blue (#0A437A). oklch(37.1% 0.105 265), rgb(36, 60, 119).
Aa
White text reads best on this color (10.56:1).
About this color
#243C77 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.105 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.025 away. White text reads best on it, at 10.56:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.105) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.98:1 |
| White text | 10.56:1 |
Values
| HEX | #243C77 |
| RGB | rgb(36, 60, 119) |
| HSL | hsl(223, 54%, 30%) |
| OKLCH | oklch(37.1% 0.105 265) |
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 #243C77 | 10.56:1 | AAA | Lc -98.2 | Preferred for body text |
| Black text on #243C77 | 1.98:1 | Fails | Lc 9.7 | Not readable |
| #243C77 text on white | 10.56:1 | AAA | Lc 94.2 | Preferred for body text |
| #243C77 text on black | 1.98:1 | Fails | Lc -8.3 | 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
#E2EAFA
oklch(93.6% 0.023 264.5)
-
Step 200
200
#CBD9F7
oklch(88.4% 0.044 265.6)
-
Step 300
300
#A8C0F5
oklch(80.9% 0.08 265.7)
-
Step 400
400
#7A9EEF
oklch(70.7% 0.126 265.1)
-
Step 500
500
#5984EA
oklch(63.2% 0.161 265)
-
Step 600
600
#3F6BD8
oklch(55.6% 0.174 264.8)
-
Step 700
700
#3258BC
oklch(49.1% 0.164 265.2)
-
Step 800
800
#2A4998
oklch(42.8% 0.135 265.1)
-
Step 900
900 (this color)
#243C77
oklch(37.1% 0.105 265)
-
Step 950
950
#162547
oklch(27.1% 0.066 264.5)
#243C77 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) | #1D4379 | 0.020 |
| Deuteranopia (no green cones) | #0B3B76 | 0.022 |
| Tritanopia (no blue cones) | #004A53 | 0.088 |
| Achromatopsia (no color) | #3F3F3F | 0.105 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243C77
#243C77
oklch(37.1% 0.105 265)
- #523C00
#523C00
oklch(37.1% 0.076 85.3)
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 #243C77, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.025
- Marine Blue #01386A ΔE 0.039
- Cobalt #1E488F ΔE 0.049
- Prussian Blue #1D3557 ΔE 0.058
- Light Navy #155084 ΔE 0.059
- Dark Slate Blue #483D8B ΔE 0.063
- Dark Grey Blue #29465B ΔE 0.063
- Marine #042E60 ΔE 0.066
Use #243C77 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.