#243C64
Closest named color: Prussian Blue (#1D3557). oklch(35.8% 0.076 260.1), rgb(36, 60, 100).
Aa
White text reads best on this color (11.02:1).
About this color
#243C64 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.076 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.031 away. White text reads best on it, at 11.02:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.076) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.90:1 |
| White text | 11.02:1 |
Values
| HEX | #243C64 |
| RGB | rgb(36, 60, 100) |
| HSL | hsl(218, 47%, 27%) |
| OKLCH | oklch(35.8% 0.076 260.1) |
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 #243C64 | 11.02:1 | AAA | Lc -99.2 | Preferred for body text |
| Black text on #243C64 | 1.90:1 | Fails | Lc 8.6 | Not readable |
| #243C64 text on white | 11.02:1 | AAA | Lc 95.3 | Preferred for body text |
| #243C64 text on black | 1.90:1 | Fails | Lc -7.3 | 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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E4EAF5
oklch(93.6% 0.016 262.8)
-
Step 200
200
#CDDAEF
oklch(88.5% 0.032 260)
-
Step 300
300
#ACC2E6
oklch(81% 0.056 260.2)
-
Step 400
400
#7FA2DA
oklch(70.8% 0.091 259.6)
-
Step 500
500
#5F89D0
oklch(63.1% 0.117 260.4)
-
Step 600
600
#4572BD
oklch(55.6% 0.127 260.1)
-
Step 700
700
#375FA3
oklch(49.1% 0.118 260.3)
-
Step 800
800
#2E4E84
oklch(42.7% 0.098 260.3)
-
Step 900
900 (this color)
#243C64
oklch(35.8% 0.076 260.1)
-
Step 950
950
#18263E
oklch(26.9% 0.049 260.7)
#243C64 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) | #2B3F66 | 0.014 |
| Deuteranopia (no green cones) | #223963 | 0.010 |
| Tritanopia (no blue cones) | #00454B | 0.065 |
| Achromatopsia (no color) | #3C3C3C | 0.076 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243C64
#243C64
oklch(35.8% 0.076 260.1)
- #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 #243C64, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.031
- Marine Blue #01386A ΔE 0.034
- Dark Grey Blue #29465B ΔE 0.040
- Twilight Blue #0A437A ΔE 0.042
- Dark Blue Grey #1F3B4D ΔE 0.042
- Charcoal #264653 ΔE 0.050
- Midnight Green #073B4C ΔE 0.052
- Marine #042E60 ΔE 0.056
Use #243C64 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.