#3F4B78
Closest named color: Dusk (#4E5481). oklch(42.4% 0.077 271.5), rgb(63, 75, 120).
Aa
White text reads best on this color (8.43:1).
About this color
#3F4B78 is a dark, moderately saturated blue. In OKLCH its lightness is 42%, its chroma 0.077 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Dusk (#4E5481), ΔE 0.038 away. White text reads best on it, at 8.43:1.
| Hue family | Blues |
| Lightness | dark (42%) |
| Chroma | moderately saturated (0.077) |
| Temperature | cool |
| Nearest name | Dusk (#4E5481) |
| Black text | 2.48:1 |
| White text | 8.43:1 |
Values
| HEX | #3F4B78 |
| RGB | rgb(63, 75, 120) |
| HSL | hsl(227, 31%, 36%) |
| OKLCH | oklch(42.4% 0.077 271.5) |
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 #3F4B78 | 8.43:1 | AAA | Lc -93.6 | Preferred for body text |
| Black text on #3F4B78 | 2.48:1 | Fails | Lc 15.0 | Not readable |
| #3F4B78 text on white | 8.43:1 | AAA | Lc 89.0 | Fine for body text |
| #3F4B78 text on black | 2.48:1 | Fails | Lc -13.2 | 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
#E6EAF3
oklch(93.7% 0.013 266.7)
-
Step 200
200
#D3D9EA
oklch(88.6% 0.024 270.3)
-
Step 300
300
#B6C0DE
oklch(81% 0.044 270.8)
-
Step 400
400
#909FCE
oklch(70.8% 0.071 270.8)
-
Step 500
500
#7586C1
oklch(63% 0.091 271.3)
-
Step 600
600
#5E6FAE
oklch(55.6% 0.1 271.4)
-
Step 700
700
#4E5D95
oklch(49.2% 0.092 271.3)
-
Step 800
800 (this color)
#3F4B78
oklch(42.4% 0.077 271.5)
-
Step 900
900
#363F61
oklch(37.6% 0.06 272)
-
Step 950
950
#202539
oklch(26.9% 0.038 272.9)
#3F4B78 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) | #3B507A | 0.015 |
| Deuteranopia (no green cones) | #354B77 | 0.014 |
| Tritanopia (no blue cones) | #2A545C | 0.067 |
| Achromatopsia (no color) | #4D4D4D | 0.077 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F4B78
#3F4B78
oklch(42.4% 0.077 271.5)
- #5D4C13
#5D4C13
oklch(42.3% 0.076 91.7)
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 #3F4B78, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dusk #4E5481 ΔE 0.038
- Twilight #4E518B ΔE 0.042
- Dusk Blue #26538D ΔE 0.044
- Light Navy #155084 ΔE 0.044
- YInMn Blue #415A77 ΔE 0.047
- Light Navy Blue #2E5A88 ΔE 0.047
- Deep Sea Blue #015482 ΔE 0.051
- Dusty Grape #545775 ΔE 0.052
Use #3F4B78 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.