#3F4374
Closest named color: Dark Slate Blue (#483D8B). oklch(40.3% 0.082 278.5), rgb(63, 67, 116).
Aa
White text reads best on this color (9.26:1).
About this color
#3F4374 is a dark, moderately saturated blue. In OKLCH its lightness is 40%, its chroma 0.082 and its hue 279°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.046 away. White text reads best on it, at 9.26:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.082) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.26:1 |
| White text | 9.26:1 |
Values
| HEX | #3F4374 |
| RGB | rgb(63, 67, 116) |
| HSL | hsl(235, 30%, 35%) |
| OKLCH | oklch(40.3% 0.082 278.5) |
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 #3F4374 | 9.26:1 | AAA | Lc -95.6 | Preferred for body text |
| Black text on #3F4374 | 2.26:1 | Fails | Lc 12.7 | Not readable |
| #3F4374 text on white | 9.26:1 | AAA | Lc 91.3 | Preferred for body text |
| #3F4374 text on black | 2.26:1 | Fails | Lc -11.1 | 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 800.
-
Step 50
50
#F4F5FA
oklch(97.1% 0.007 277.2)
-
Step 100
100
#E7E9F3
oklch(93.5% 0.014 277.1)
-
Step 200
200
#D5D8EB
oklch(88.6% 0.026 278.7)
-
Step 300
300
#B9BEE0
oklch(80.9% 0.048 278.7)
-
Step 400
400
#959CD0
oklch(70.6% 0.076 278.3)
-
Step 500
500
#7C83C4
oklch(63.1% 0.098 278.5)
-
Step 600
600
#666CB1
oklch(55.7% 0.107 278.6)
-
Step 700
700
#555A98
oklch(49.2% 0.099 278.6)
-
Step 800
800 (this color)
#3F4374
oklch(40.3% 0.082 278.5)
-
Step 900
900
#3A3E63
oklch(37.8% 0.063 278.2)
-
Step 950
950
#22243A
oklch(26.9% 0.041 279.3)
#3F4374 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) | #314976 | 0.024 |
| Deuteranopia (no green cones) | #2D4573 | 0.025 |
| Tritanopia (no blue cones) | #2E4D56 | 0.071 |
| Achromatopsia (no color) | #474747 | 0.082 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F4374
#3F4374
oklch(40.3% 0.082 278.5)
- #544903
#544903
oklch(40.4% 0.082 99.1)
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 #3F4374, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.046
- Twilight Blue #0A437A ΔE 0.054
- Light Navy #155084 ΔE 0.055
- Cobalt #1E488F ΔE 0.056
- Dark Grey Blue #29465B ΔE 0.056
- Twilight #4E518B ΔE 0.058
- Dusk #4E5481 ΔE 0.058
- Dusk Blue #26538D ΔE 0.059
Use #3F4374 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.