#243C63
Closest named color: Prussian Blue (#1D3557). oklch(35.7% 0.074 259.7), rgb(36, 60, 99).
Aa
White text reads best on this color (11.04:1).
About this color
#243C63 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.074 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.030 away. White text reads best on it, at 11.04:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.074) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.90:1 |
| White text | 11.04:1 |
Values
| HEX | #243C63 |
| RGB | rgb(36, 60, 99) |
| HSL | hsl(217, 47%, 26%) |
| OKLCH | oklch(35.7% 0.074 259.7) |
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 #243C63 | 11.04:1 | AAA | Lc -99.2 | Preferred for body text |
| Black text on #243C63 | 1.90:1 | Fails | Lc 8.5 | Not readable |
| #243C63 text on white | 11.04:1 | AAA | Lc 95.4 | Preferred for body text |
| #243C63 text on black | 1.90:1 | Fails | Lc 0.0 | 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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E4EAF5
oklch(93.6% 0.016 262.8)
-
Step 200
200
#CDDAEE
oklch(88.5% 0.031 258.9)
-
Step 300
300
#ACC2E5
oklch(80.9% 0.055 259.6)
-
Step 400
400
#80A2D9
oklch(70.8% 0.089 259.8)
-
Step 500
500
#5F8ACE
oklch(63.2% 0.114 259.3)
-
Step 600
600
#4672BB
oklch(55.5% 0.124 260)
-
Step 700
700
#3760A1
oklch(49.2% 0.114 259.3)
-
Step 800
800
#2E4E83
oklch(42.7% 0.096 260)
-
Step 900
900 (this color)
#243C63
oklch(35.7% 0.074 259.7)
-
Step 950
950
#18263D
oklch(26.8% 0.047 260)
#243C63 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) | #2C3F65 | 0.015 |
| Deuteranopia (no green cones) | #233962 | 0.010 |
| Tritanopia (no blue cones) | #00454A | 0.065 |
| Achromatopsia (no color) | #3C3C3C | 0.074 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243C63
#243C63
oklch(35.7% 0.074 259.7)
- #513700
#513700
oklch(35.8% 0.074 79.2)
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 #243C63, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.030
- Marine Blue #01386A ΔE 0.034
- Dark Grey Blue #29465B ΔE 0.039
- Dark Blue Grey #1F3B4D ΔE 0.040
- Twilight Blue #0A437A ΔE 0.043
- Charcoal #264653 ΔE 0.049
- Midnight Green #073B4C ΔE 0.050
- Marine #042E60 ΔE 0.056
Use #243C63 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.