#3F447D
Closest named color: Dark Slate Blue (#483D8B). oklch(41.1% 0.095 277.6), rgb(63, 68, 125).
Aa
White text reads best on this color (8.99:1).
About this color
#3F447D is a dark, moderately saturated blue. In OKLCH its lightness is 41%, its chroma 0.095 and its hue 278°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.034 away. White text reads best on it, at 8.99:1.
| Hue family | Blues |
| Lightness | dark (41%) |
| Chroma | moderately saturated (0.095) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.33:1 |
| White text | 8.99:1 |
Values
| HEX | #3F447D |
| RGB | rgb(63, 68, 125) |
| HSL | hsl(235, 33%, 37%) |
| OKLCH | oklch(41.1% 0.095 277.6) |
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 #3F447D | 8.99:1 | AAA | Lc -94.9 | Preferred for body text |
| Black text on #3F447D | 2.33:1 | Fails | Lc 13.4 | Not readable |
| #3F447D text on white | 8.99:1 | AAA | Lc 90.5 | Preferred for body text |
| #3F447D text on black | 2.33:1 | Fails | Lc -11.8 | 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 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
#D4D8EE
oklch(88.6% 0.03 277.6)
-
Step 300
300
#B7BEE5
oklch(80.9% 0.056 277.1)
-
Step 400
400
#939CD8
oklch(70.8% 0.088 277.3)
-
Step 500
500
#7982CD
oklch(63.1% 0.113 277.4)
-
Step 600
600
#636ABA
oklch(55.6% 0.123 277.8)
-
Step 700
700
#5258A0
oklch(49% 0.114 277.7)
-
Step 800
800 (this color)
#3F447D
oklch(41.1% 0.095 277.6)
-
Step 900
900
#383D68
oklch(37.7% 0.074 277.2)
-
Step 950
950
#21243D
oklch(27% 0.047 277.6)
#3F447D 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) | #2D4C7F | 0.030 |
| Deuteranopia (no green cones) | #28477C | 0.030 |
| Tritanopia (no blue cones) | #28505A | 0.083 |
| Achromatopsia (no color) | #494949 | 0.095 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F447D
#3F447D
oklch(41.1% 0.095 277.6)
- #574A00
#574A00
oklch(41% 0.085 97.6)
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 #3F447D, 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 0.045
- Cobalt #1E488F ΔE 0.046
- Twilight #4E518B ΔE 0.049
- Light Navy #155084 ΔE 0.050
- Dusk Blue #26538D ΔE 0.050
- Dusk #4E5481 ΔE 0.054
- Twilight Blue #0A437A ΔE 0.055
Use #3F447D 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.