#042539
Closest named color: Oxford Blue (#1B263B). oklch(25.3% 0.053 240.2), rgb(4, 37, 57).
Aa
White text reads best on this color (15.80:1).
About this color
#042539 is a dark, muted blue. In OKLCH its lightness is 25%, its chroma 0.053 and its hue 240°. Its hue sits on the cool side of the wheel. The nearest named color is Oxford Blue (#1B263B), ΔE 0.027 away. White text reads best on it, at 15.80:1.
| Hue family | Blues |
| Lightness | dark (25%) |
| Chroma | muted (0.053) |
| Temperature | cool |
| Nearest name | Oxford Blue (#1B263B) |
| Black text | 1.32:1 |
| White text | 15.80:1 |
Values
| HEX | #042539 |
| RGB | rgb(4, 37, 57) |
| HSL | hsl(203, 87%, 12%) |
| OKLCH | oklch(25.3% 0.053 240.2) |
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 #042539 | 15.80:1 | AAA | Lc -105.2 | Preferred for body text |
| Black text on #042539 | 1.32:1 | Fails | Lc 0.0 | Not readable |
| #042539 text on white | 15.80:1 | AAA | Lc 102.5 | Preferred for body text |
| #042539 text on black | 1.32:1 | 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 950.
-
Step 50
50
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E0ECF5
oklch(93.7% 0.018 240)
-
Step 200
200
#C5DDEE
oklch(88.5% 0.035 238.7)
-
Step 300
300
#9CC7E6
oklch(81% 0.063 239.9)
-
Step 400
400
#62A9D9
oklch(70.7% 0.101 239.9)
-
Step 500
500
#2C92CF
oklch(63.1% 0.129 240.3)
-
Step 600
600
#007BB6
oklch(55.6% 0.128 240.2)
-
Step 700
700
#00679A
oklch(49.1% 0.113 240.5)
-
Step 800
800
#00547F
oklch(42.6% 0.099 240.7)
-
Step 900
900
#054669
oklch(37.6% 0.084 240.3)
-
Step 950
950 (this color)
#042539
oklch(25.3% 0.053 240.2)
#042539 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) | #1B253A | 0.026 |
| Deuteranopia (no green cones) | #142039 | 0.022 |
| Tritanopia (no blue cones) | #002A2C | 0.035 |
| Achromatopsia (no color) | #232323 | 0.053 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #042539
#042539
oklch(25.3% 0.053 240.2)
- #341B04
#341B04
oklch(25.2% 0.053 60.1)
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 #042539, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Oxford Blue #1B263B ΔE 0.027
- Dark #1B2431 ΔE 0.028
- Rich Black #0D1B2A ΔE 0.040
- Jet #212529 ΔE 0.045
- Space Cadet #2B2D42 ΔE 0.062
- Gunmetal #293241 ΔE 0.068
- Navy Blue #001146 ΔE 0.071
- Marine #042E60 ΔE 0.074
Use #042539 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.