#3F4288
Closest named color: Dark Slate Blue (#483D8B). oklch(41.4% 0.114 278.3), rgb(63, 66, 136).
Aa
White text reads best on this color (8.95:1).
About this color
#3F4288 is a dark, moderately saturated blue. In OKLCH its lightness is 41%, its chroma 0.114 and its hue 278°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.019 away. White text reads best on it, at 8.95:1.
| Hue family | Blues |
| Lightness | dark (41%) |
| Chroma | moderately saturated (0.114) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.34:1 |
| White text | 8.95:1 |
Values
| HEX | #3F4288 |
| RGB | rgb(63, 66, 136) |
| HSL | hsl(238, 37%, 39%) |
| OKLCH | oklch(41.4% 0.114 278.3) |
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 #3F4288 | 8.95:1 | AAA | Lc -94.8 | Preferred for body text |
| Black text on #3F4288 | 2.34:1 | Fails | Lc 13.6 | Not readable |
| #3F4288 text on white | 8.95:1 | AAA | Lc 90.3 | Preferred for body text |
| #3F4288 text on black | 2.34:1 | Fails | Lc -12.0 | 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
#F4F5FC
oklch(97.1% 0.009 279.7)
-
Step 100
100
#E6E9F7
oklch(93.6% 0.019 276.3)
-
Step 200
200
#D3D7F2
oklch(88.4% 0.037 278.9)
-
Step 300
300
#B6BDEC
oklch(80.9% 0.067 278.2)
-
Step 400
400
#919AE3
oklch(70.8% 0.107 277.9)
-
Step 500
500
#787FDA
oklch(63.1% 0.136 278.4)
-
Step 600
600
#6266C8
oklch(55.6% 0.149 278.6)
-
Step 700
700
#5154AD
oklch(49% 0.139 278.5)
-
Step 800
800 (this color)
#3F4288
oklch(41.4% 0.114 278.3)
-
Step 900
900
#383B70
oklch(37.7% 0.089 278.7)
-
Step 950
950
#202341
oklch(27% 0.056 277.7)
#3F4288 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) | #204C8B | 0.041 |
| Deuteranopia (no green cones) | #184786 | 0.044 |
| Tritanopia (no blue cones) | #20515E | 0.100 |
| Achromatopsia (no color) | #494949 | 0.115 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F4288
#3F4288
oklch(41.4% 0.114 278.3)
- #584B00
#584B00
oklch(41.3% 0.085 97.7)
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 #3F4288, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.019
- Blueberry #464196 ΔE 0.026
- Cobalt #1E488F ΔE 0.040
- Twilight #4E518B ΔE 0.050
- Dusk Blue #26538D ΔE 0.051
- Light Navy #155084 ΔE 0.055
- Twilight Blue #0A437A ΔE 0.060
- Dusk #4E5481 ΔE 0.062
Use #3F4288 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.