#3F407D
Closest named color: Dark Slate Blue (#483D8B). oklch(40.3% 0.101 280.2), rgb(63, 64, 125).
Aa
White text reads best on this color (9.37:1).
About this color
#3F407D is a dark, moderately saturated purple. In OKLCH its lightness is 40%, its chroma 0.101 and its hue 280°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.029 away. White text reads best on it, at 9.37:1.
| Hue family | Purples |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.101) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.24:1 |
| White text | 9.37:1 |
Values
| HEX | #3F407D |
| RGB | rgb(63, 64, 125) |
| HSL | hsl(239, 33%, 37%) |
| OKLCH | oklch(40.3% 0.101 280.2) |
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 #3F407D | 9.37:1 | AAA | Lc -95.8 | Preferred for body text |
| Black text on #3F407D | 2.24:1 | Fails | Lc 12.5 | Not readable |
| #3F407D text on white | 9.37:1 | AAA | Lc 91.5 | Preferred for body text |
| #3F407D text on black | 2.24:1 | Fails | Lc -10.9 | 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
#F4F5FB
oklch(97.1% 0.008 278.6)
-
Step 100
100
#E7E9F5
oklch(93.6% 0.016 278.5)
-
Step 200
200
#D4D7EF
oklch(88.4% 0.033 280)
-
Step 300
300
#B9BDE7
oklch(80.9% 0.059 280.7)
-
Step 400
400
#959ADB
oklch(70.7% 0.095 280.3)
-
Step 500
500
#7C80D1
oklch(63.1% 0.121 280.2)
-
Step 600
600
#6668BE
oklch(55.6% 0.131 280.2)
-
Step 700
700
#5556A4
oklch(49.1% 0.122 280.3)
-
Step 800
800 (this color)
#3F407D
oklch(40.3% 0.101 280.2)
-
Step 900
900
#3A3C6A
oklch(37.7% 0.078 280.1)
-
Step 950
950
#22233E
oklch(26.9% 0.05 280.9)
#3F407D 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) | #26497F | 0.038 |
| Deuteranopia (no green cones) | #22447C | 0.037 |
| Tritanopia (no blue cones) | #294D58 | 0.088 |
| Achromatopsia (no color) | #464646 | 0.101 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F407D
#3F407D
oklch(40.3% 0.101 280.2)
- #534900
#534900
oklch(40.3% 0.084 100.4)
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 #3F407D, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.029
- Blueberry #464196 ΔE 0.043
- Cobalt #1E488F ΔE 0.048
- Twilight Blue #0A437A ΔE 0.055
- Light Navy #155084 ΔE 0.057
- Twilight #4E518B ΔE 0.058
- Dusk Blue #26538D ΔE 0.059
- Dusk #4E5481 ΔE 0.064
Use #3F407D 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.