#043F71
Closest named color: Twilight Blue (#0A437A). oklch(36.3% 0.102 250.9), rgb(4, 63, 113).
Aa
White text reads best on this color (10.74:1).
About this color
#043F71 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.102 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.019 away. White text reads best on it, at 10.74:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.102) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.95:1 |
| White text | 10.74:1 |
Values
| HEX | #043F71 |
| RGB | rgb(4, 63, 113) |
| HSL | hsl(208, 93%, 23%) |
| OKLCH | oklch(36.3% 0.102 250.9) |
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 #043F71 | 10.74:1 | AAA | Lc -98.4 | Preferred for body text |
| Black text on #043F71 | 1.95:1 | Fails | Lc 9.5 | Not readable |
| #043F71 text on white | 10.74:1 | AAA | Lc 94.4 | Preferred for body text |
| #043F71 text on black | 1.95:1 | Fails | Lc -8.2 | 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
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#DFEBF9
oklch(93.5% 0.023 252.2)
-
Step 200
200
#C5DCF5
oklch(88.5% 0.042 250.5)
-
Step 300
300
#9CC5F1
oklch(81% 0.076 250.6)
-
Step 400
400
#63A5EA
oklch(70.7% 0.122 250.9)
-
Step 500
500
#308DE4
oklch(63.2% 0.156 250.7)
-
Step 600
600
#0075CD
oklch(55.6% 0.161 250.9)
-
Step 700
700
#0062AE
oklch(49.1% 0.143 251.1)
-
Step 800
800
#00508F
oklch(42.6% 0.123 250.8)
-
Step 900
900 (this color)
#043F71
oklch(36.3% 0.102 250.9)
-
Step 950
950
#092845
oklch(27.1% 0.065 250.4)
#043F71 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) | #254373 | 0.029 |
| Deuteranopia (no green cones) | #113970 | 0.018 |
| Tritanopia (no blue cones) | #004B52 | 0.074 |
| Achromatopsia (no color) | #3E3E3E | 0.102 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #043F71
#043F71
oklch(36.3% 0.102 250.9)
- #573600
#573600
oklch(36.4% 0.078 71.8)
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 #043F71, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.019
- Marine Blue #01386A ΔE 0.024
- Prussian Blue #1D3557 ΔE 0.050
- Dark Grey Blue #29465B ΔE 0.056
- Marine #042E60 ΔE 0.057
- Light Navy #155084 ΔE 0.059
- Cobalt #1E488F ΔE 0.060
- Dark Blue Grey #1F3B4D ΔE 0.062
Use #043F71 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.