#243C55
Closest named color: Dark Blue Grey (#1F3B4D). oklch(34.9% 0.053 250.5), rgb(36, 60, 85).
Aa
White text reads best on this color (11.33:1).
About this color
#243C55 is a dark, muted blue. In OKLCH its lightness is 35%, its chroma 0.053 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.016 away. White text reads best on it, at 11.33:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | muted (0.053) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.85:1 |
| White text | 11.33:1 |
Values
| HEX | #243C55 |
| RGB | rgb(36, 60, 85) |
| HSL | hsl(211, 40%, 24%) |
| OKLCH | oklch(34.9% 0.053 250.5) |
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 #243C55 | 11.33:1 | AAA | Lc -99.8 | Preferred for body text |
| Black text on #243C55 | 1.85:1 | Fails | Lc 7.8 | Not readable |
| #243C55 text on white | 11.33:1 | AAA | Lc 96.1 | Preferred for body text |
| #243C55 text on black | 1.85:1 | 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
#E4EBF1
oklch(93.6% 0.011 243.7)
-
Step 200
200
#CFDBE8
oklch(88.6% 0.022 250.2)
-
Step 300
300
#AEC3DA
oklch(80.9% 0.04 250.7)
-
Step 400
400
#83A4C8
oklch(70.7% 0.064 250.9)
-
Step 500
500
#638DB9
oklch(63% 0.081 250.3)
-
Step 600
600
#4977A6
oklch(55.7% 0.089 250.2)
-
Step 700
700
#3B648E
oklch(49.2% 0.082 250.4)
-
Step 800
800
#315173
oklch(42.6% 0.068 251.1)
-
Step 900
900 (this color)
#243C55
oklch(34.9% 0.053 250.5)
-
Step 950
950
#1A2836
oklch(27.1% 0.032 249.1)
#243C55 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) | #323D56 | 0.020 |
| Deuteranopia (no green cones) | #2B3855 | 0.015 |
| Tritanopia (no blue cones) | #084245 | 0.046 |
| Achromatopsia (no color) | #3A3A3A | 0.053 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243C55
#243C55
oklch(34.9% 0.053 250.5)
- #4C3519
#4C3519
oklch(34.9% 0.053 69.9)
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 #243C55, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.016
- Prussian Blue #1D3557 ΔE 0.026
- Midnight Green #073B4C ΔE 0.031
- Dark Grey Blue #29465B ΔE 0.033
- Charcoal #264653 ΔE 0.035
- Onyx #343A40 ΔE 0.040
- Gunmetal #293241 ΔE 0.041
- Marine Blue #01386A ΔE 0.049
Use #243C55 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.