#243C59
Closest named color: Dark Blue Grey (#1F3B4D). oklch(35.1% 0.059 253.9), rgb(36, 60, 89).
Aa
White text reads best on this color (11.25:1).
About this color
#243C59 is a dark, muted blue. In OKLCH its lightness is 35%, its chroma 0.059 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.023 away. White text reads best on it, at 11.25:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | muted (0.059) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.86:1 |
| White text | 11.25:1 |
Values
| HEX | #243C59 |
| RGB | rgb(36, 60, 89) |
| HSL | hsl(213, 42%, 25%) |
| OKLCH | oklch(35.1% 0.059 253.9) |
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 #243C59 | 11.25:1 | AAA | Lc -99.7 | Preferred for body text |
| Black text on #243C59 | 1.86:1 | Fails | Lc 8.0 | Not readable |
| #243C59 text on white | 11.25:1 | AAA | Lc 95.9 | Preferred for body text |
| #243C59 text on black | 1.86:1 | 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
#F3F6F9
oklch(97.2% 0.005 247.9)
-
Step 100
100
#E4EAF2
oklch(93.5% 0.013 255.5)
-
Step 200
200
#CEDAEA
oklch(88.4% 0.026 255.6)
-
Step 300
300
#ADC3DD
oklch(80.9% 0.044 252.7)
-
Step 400
400
#82A3CD
oklch(70.6% 0.072 254.7)
-
Step 500
500
#628CBF
oklch(63% 0.09 253.9)
-
Step 600
600
#4876AC
oklch(55.7% 0.099 253.4)
-
Step 700
700
#3A6394
oklch(49.3% 0.092 253.9)
-
Step 800
800
#305178
oklch(42.8% 0.076 253.6)
-
Step 900
900 (this color)
#243C59
oklch(35.1% 0.059 253.9)
-
Step 950
950
#192738
oklch(26.9% 0.037 253.8)
#243C59 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) | #303E5A | 0.018 |
| Deuteranopia (no green cones) | #293858 | 0.013 |
| Tritanopia (no blue cones) | #034346 | 0.053 |
| Achromatopsia (no color) | #3B3B3B | 0.059 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243C59
#243C59
oklch(35.1% 0.059 253.9)
- #4D3613
#4D3613
oklch(35.2% 0.059 74.9)
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 #243C59, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.023
- Prussian Blue #1D3557 ΔE 0.025
- Dark Grey Blue #29465B ΔE 0.034
- Midnight Green #073B4C ΔE 0.036
- Charcoal #264653 ΔE 0.038
- Marine Blue #01386A ΔE 0.044
- Onyx #343A40 ΔE 0.046
- Gunmetal #293241 ΔE 0.046
Use #243C59 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.