#3F427B
Closest named color: Dark Slate Blue (#483D8B). oklch(40.6% 0.095 279), rgb(63, 66, 123).
Aa
White text reads best on this color (9.22:1).
About this color
#3F427B is a dark, moderately saturated blue. In OKLCH its lightness is 41%, its chroma 0.095 and its hue 279°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.034 away. White text reads best on it, at 9.22:1.
| Hue family | Blues |
| Lightness | dark (41%) |
| Chroma | moderately saturated (0.095) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.27:1 |
| White text | 9.22:1 |
Values
| HEX | #3F427B |
| RGB | rgb(63, 66, 123) |
| HSL | hsl(237, 32%, 36%) |
| OKLCH | oklch(40.6% 0.095 279) |
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 #3F427B | 9.22:1 | AAA | Lc -95.5 | Preferred for body text |
| Black text on #3F427B | 2.27:1 | Fails | Lc 12.8 | Not readable |
| #3F427B text on white | 9.22:1 | AAA | Lc 91.1 | Preferred for body text |
| #3F427B text on black | 2.27:1 | Fails | Lc -11.2 | 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 800.
-
Step 50
50
#F4F5FA
oklch(97.1% 0.007 277.2)
-
Step 100
100
#E7E9F5
oklch(93.6% 0.016 278.5)
-
Step 200
200
#D4D8EE
oklch(88.6% 0.03 277.6)
-
Step 300
300
#B8BEE5
oklch(81% 0.055 278.2)
-
Step 400
400
#949BD7
oklch(70.6% 0.088 278.7)
-
Step 500
500
#7B81CD
oklch(63% 0.114 279.2)
-
Step 600
600
#656AB9
oklch(55.7% 0.121 278.9)
-
Step 700
700
#5458A0
oklch(49.2% 0.114 278.9)
-
Step 800
800 (this color)
#3F427B
oklch(40.6% 0.095 279)
-
Step 900
900
#393D68
oklch(37.7% 0.073 278.2)
-
Step 950
950
#22243D
oklch(27.1% 0.046 279.3)
#3F427B 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) | #2B4A7D | 0.032 |
| Deuteranopia (no green cones) | #27457A | 0.032 |
| Tritanopia (no blue cones) | #2A4E58 | 0.083 |
| Achromatopsia (no color) | #474747 | 0.095 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F427B
#3F427B
oklch(40.6% 0.095 279)
- #554900
#554900
oklch(40.5% 0.084 98.4)
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 #3F427B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.034
- Blueberry #464196 ΔE 0.047
- Cobalt #1E488F ΔE 0.049
- Light Navy #155084 ΔE 0.054
- Twilight Blue #0A437A ΔE 0.054
- Twilight #4E518B ΔE 0.054
- Dusk Blue #26538D ΔE 0.056
- Dusk #4E5481 ΔE 0.059
Use #3F427B 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.