#3F487D
Closest named color: Twilight (#4E518B). oklch(42% 0.089 274.7), rgb(63, 72, 125).
Aa
White text reads best on this color (8.62:1).
About this color
#3F487D is a dark, moderately saturated blue. In OKLCH its lightness is 42%, its chroma 0.089 and its hue 275°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight (#4E518B), ΔE 0.041 away. White text reads best on it, at 8.62:1.
| Hue family | Blues |
| Lightness | dark (42%) |
| Chroma | moderately saturated (0.089) |
| Temperature | cool |
| Nearest name | Twilight (#4E518B) |
| Black text | 2.43:1 |
| White text | 8.62:1 |
Values
| HEX | #3F487D |
| RGB | rgb(63, 72, 125) |
| HSL | hsl(231, 33%, 37%) |
| OKLCH | oklch(42% 0.089 274.7) |
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 #3F487D | 8.62:1 | AAA | Lc -94.0 | Preferred for body text |
| Black text on #3F487D | 2.43:1 | Fails | Lc 14.5 | Not readable |
| #3F487D text on white | 8.62:1 | AAA | Lc 89.5 | Fine for body text |
| #3F487D text on black | 2.43:1 | Fails | Lc -12.7 | 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
#E7E9F4
oklch(93.6% 0.015 277.8)
-
Step 200
200
#D3D8ED
oklch(88.5% 0.029 275.1)
-
Step 300
300
#B6BFE3
oklch(81% 0.052 274.2)
-
Step 400
400
#919DD5
oklch(70.7% 0.083 274.7)
-
Step 500
500
#7684C9
oklch(63.1% 0.105 274.3)
-
Step 600
600
#606CB6
oklch(55.5% 0.115 275)
-
Step 700
700
#4F5A9D
oklch(49.1% 0.108 274.7)
-
Step 800
800 (this color)
#3F487D
oklch(42% 0.089 274.7)
-
Step 900
900
#373E66
oklch(37.7% 0.069 275.1)
-
Step 950
950
#20253C
oklch(27.1% 0.043 273.8)
#3F487D 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) | #344E7F | 0.021 |
| Deuteranopia (no green cones) | #2E497C | 0.022 |
| Tritanopia (no blue cones) | #28535C | 0.079 |
| Achromatopsia (no color) | #4C4C4C | 0.089 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F487D
#3F487D
oklch(42% 0.089 274.7)
- #5C4C00
#5C4C00
oklch(42% 0.086 95.1)
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 #3F487D, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight #4E518B ΔE 0.041
- Dark Slate Blue #483D8B ΔE 0.042
- Dusk Blue #26538D ΔE 0.043
- Dusk #4E5481 ΔE 0.044
- Light Navy #155084 ΔE 0.044
- Cobalt #1E488F ΔE 0.047
- Blueberry #464196 ΔE 0.049
- Light Navy Blue #2E5A88 ΔE 0.053
Use #3F487D 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.