#243F59
Closest named color: Dark Grey Blue (#29465B). oklch(35.9% 0.056 248.8), rgb(36, 63, 89).
Aa
White text reads best on this color (10.87:1).
About this color
#243F59 is a dark, muted blue. In OKLCH its lightness is 36%, its chroma 0.056 and its hue 249°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Grey Blue (#29465B), ΔE 0.024 away. White text reads best on it, at 10.87:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | muted (0.056) |
| Temperature | cool |
| Nearest name | Dark Grey Blue (#29465B) |
| Black text | 1.93:1 |
| White text | 10.87:1 |
Values
| HEX | #243F59 |
| RGB | rgb(36, 63, 89) |
| HSL | hsl(209, 42%, 25%) |
| OKLCH | oklch(35.9% 0.056 248.8) |
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 #243F59 | 10.87:1 | AAA | Lc -99.0 | Preferred for body text |
| Black text on #243F59 | 1.93:1 | Fails | Lc 8.8 | Not readable |
| #243F59 text on white | 10.87:1 | AAA | Lc 95.1 | Preferred for body text |
| #243F59 text on black | 1.93:1 | Fails | Lc -7.5 | 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
#E4EBF2
oklch(93.7% 0.012 248)
-
Step 200
200
#CEDBE8
oklch(88.6% 0.023 248.1)
-
Step 300
300
#ACC4DB
oklch(81% 0.042 247.2)
-
Step 400
400
#80A5C9
oklch(70.8% 0.067 248.1)
-
Step 500
500
#5F8EBC
oklch(63.2% 0.087 248.8)
-
Step 600
600
#4477A8
oklch(55.5% 0.094 249)
-
Step 700
700
#366490
oklch(49.1% 0.087 249.1)
-
Step 800
800
#2D5275
oklch(42.8% 0.072 248.6)
-
Step 900
900 (this color)
#243F59
oklch(35.9% 0.056 248.8)
-
Step 950
950
#182837
oklch(27% 0.035 247.7)
#243F59 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) | #34405A | 0.022 |
| Deuteranopia (no green cones) | #2D3B58 | 0.016 |
| Tritanopia (no blue cones) | #024548 | 0.048 |
| Achromatopsia (no color) | #3D3D3D | 0.056 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #243F59
#243F59
oklch(35.9% 0.056 248.8)
- #50371A
#50371A
oklch(35.9% 0.056 68.4)
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 #243F59, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Grey Blue #29465B ΔE 0.024
- Dark Blue Grey #1F3B4D ΔE 0.024
- Charcoal #264653 ΔE 0.028
- Prussian Blue #1D3557 ΔE 0.034
- Midnight Green #073B4C ΔE 0.037
- Onyx #343A40 ΔE 0.045
- Marine Blue #01386A ΔE 0.050
- Gunmetal #293241 ΔE 0.051
Use #243F59 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.