#042540
Closest named color: Oxford Blue (#1B263B). oklch(25.8% 0.063 247.8), rgb(4, 37, 64).
Aa
White text reads best on this color (15.62:1).
About this color
#042540 is a dark, muted blue. In OKLCH its lightness is 26%, its chroma 0.063 and its hue 248°. 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 15.62:1.
| Hue family | Blues |
| Lightness | dark (26%) |
| Chroma | muted (0.063) |
| Temperature | cool |
| Nearest name | Oxford Blue (#1B263B) |
| Black text | 1.34:1 |
| White text | 15.62:1 |
Values
| HEX | #042540 |
| RGB | rgb(4, 37, 64) |
| HSL | hsl(207, 88%, 13%) |
| OKLCH | oklch(25.8% 0.063 247.8) |
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 #042540 | 15.62:1 | AAA | Lc -105.0 | Preferred for body text |
| Black text on #042540 | 1.34:1 | Fails | Lc 0.0 | Not readable |
| #042540 text on white | 15.62:1 | AAA | Lc 102.3 | Preferred for body text |
| #042540 text on black | 1.34:1 | 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
#F0F6FC
oklch(97% 0.01 247.9)
-
Step 100
100
#DFECF8
oklch(93.7% 0.021 245.9)
-
Step 200
200
#C4DCF4
oklch(88.4% 0.042 248.3)
-
Step 300
300
#9AC6EF
oklch(81% 0.075 247)
-
Step 400
400
#5FA6E7
oklch(70.6% 0.12 247.9)
-
Step 500
500
#278EE0
oklch(63% 0.153 247.9)
-
Step 600
600
#0077C5
oklch(55.6% 0.149 247.9)
-
Step 700
700
#0064A7
oklch(49.1% 0.132 247.9)
-
Step 800
800
#00528A
oklch(42.8% 0.115 247.8)
-
Step 900
900
#024473
oklch(37.7% 0.099 247.7)
-
Step 950
950 (this color)
#042540
oklch(25.8% 0.063 247.8)
#042540 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) | #182641 | 0.022 |
| Deuteranopia (no green cones) | #0F213F | 0.015 |
| Tritanopia (no blue cones) | #002C2F | 0.046 |
| Achromatopsia (no color) | #232323 | 0.063 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #042540
#042540
oklch(25.8% 0.063 247.8)
- #351D00
#351D00
oklch(25.7% 0.057 67.4)
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 #042540, 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 0.036
- Rich Black #0D1B2A ΔE 0.049
- Jet #212529 ΔE 0.054
- Space Cadet #2B2D42 ΔE 0.060
- Marine #042E60 ΔE 0.062
- Navy Blue #001146 ΔE 0.065
- Gunmetal #293241 ΔE 0.067
Use #042540 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.