#3F407B
Closest named color: Dark Slate Blue (#483D8B). oklch(40.1% 0.098 280.3), rgb(63, 64, 123).
Aa
White text reads best on this color (9.41:1).
About this color
#3F407B is a dark, moderately saturated purple. In OKLCH its lightness is 40%, its chroma 0.098 and its hue 280°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.032 away. White text reads best on it, at 9.41:1.
| Hue family | Purples |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.098) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.23:1 |
| White text | 9.41:1 |
Values
| HEX | #3F407B |
| RGB | rgb(63, 64, 123) |
| HSL | hsl(239, 32%, 36%) |
| OKLCH | oklch(40.1% 0.098 280.3) |
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 #3F407B | 9.41:1 | AAA | Lc -95.9 | Preferred for body text |
| Black text on #3F407B | 2.23:1 | Fails | Lc 12.3 | Not readable |
| #3F407B text on white | 9.41:1 | AAA | Lc 91.6 | Preferred for body text |
| #3F407B text on black | 2.23:1 | Fails | Lc -10.8 | 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
#F4F5FC
oklch(97.1% 0.009 279.7)
-
Step 100
100
#E7E9F8
oklch(93.7% 0.02 279.9)
-
Step 200
200
#D3D7F4
oklch(88.5% 0.04 279.3)
-
Step 300
300
#B7BCF0
oklch(80.9% 0.073 280.3)
-
Step 400
400
#9398E8
oklch(70.8% 0.116 280.2)
-
Step 500
500
#7A7CE1
oklch(63.1% 0.149 280.4)
-
Step 600
600
#6463CF
oklch(55.6% 0.162 280.1)
-
Step 700
700
#5351B3
oklch(49% 0.151 280.2)
-
Step 800
800
#444391
oklch(42.7% 0.125 280.3)
-
Step 900
900 (this color)
#3F407B
oklch(40.1% 0.098 280.3)
-
Step 950
950
#212244
oklch(27% 0.062 280.1)
#3F407B 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) | #28487D | 0.035 |
| Deuteranopia (no green cones) | #24447A | 0.036 |
| Tritanopia (no blue cones) | #2A4C57 | 0.084 |
| Achromatopsia (no color) | #464646 | 0.098 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F407B
#3F407B
oklch(40.1% 0.098 280.3)
- #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 #3F407B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.032
- Blueberry #464196 ΔE 0.046
- Cobalt #1E488F ΔE 0.050
- Twilight Blue #0A437A ΔE 0.054
- Light Navy #155084 ΔE 0.058
- Twilight #4E518B ΔE 0.059
- Dusk Blue #26538D ΔE 0.060
- Dusk #4E5481 ΔE 0.064
Use #3F407B 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.