#3F508B
Closest named color: Twilight (#4E518B). oklch(44.7% 0.099 269.9), rgb(63, 80, 139).
Aa
White text reads best on this color (7.68:1).
About this color
#3F508B is a dark, moderately saturated blue. In OKLCH its lightness is 45%, its chroma 0.099 and its hue 270°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight (#4E518B), ΔE 0.022 away. White text reads best on it, at 7.68:1.
| Hue family | Blues |
| Lightness | dark (45%) |
| Chroma | moderately saturated (0.099) |
| Temperature | cool |
| Nearest name | Twilight (#4E518B) |
| Black text | 2.73:1 |
| White text | 7.68:1 |
Values
| HEX | #3F508B |
| RGB | rgb(63, 80, 139) |
| HSL | hsl(227, 38%, 40%) |
| OKLCH | oklch(44.7% 0.099 269.9) |
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 #3F508B | 7.68:1 | AAA | Lc -91.3 | Preferred for body text |
| Black text on #3F508B | 2.73:1 | Fails | Lc 17.4 | Dividers and decoration only |
| #3F508B text on white | 7.68:1 | AAA | Lc 86.6 | Fine for body text |
| #3F508B text on black | 2.73:1 | Fails | Lc -15.5 | Dividers and decoration only |
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
#F3F5FB
oklch(97% 0.008 271.3)
-
Step 100
100
#E5EAF6
oklch(93.7% 0.017 267.8)
-
Step 200
200
#D1D9EF
oklch(88.6% 0.031 269.8)
-
Step 300
300
#B2C0E7
oklch(81% 0.057 269.6)
-
Step 400
400
#8A9EDB
oklch(70.7% 0.093 270)
-
Step 500
500
#6D85D1
oklch(63.1% 0.118 269.5)
-
Step 600
600
#566DBE
oklch(55.5% 0.129 269.9)
-
Step 700
700
#475BA4
oklch(49.2% 0.119 270)
-
Step 800
800 (this color)
#3F508B
oklch(44.7% 0.099 269.9)
-
Step 900
900
#323F6B
oklch(37.9% 0.077 270)
-
Step 950
950
#1D253E
oklch(27% 0.048 269.5)
#3F508B 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) | #38578D | 0.020 |
| Deuteranopia (no green cones) | #2F508A | 0.019 |
| Tritanopia (no blue cones) | #1A5D66 | 0.090 |
| Achromatopsia (no color) | #535353 | 0.099 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F508B
#3F508B
oklch(44.7% 0.099 269.9)
- #685100
#685100
oklch(44.6% 0.091 89.7)
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 #3F508B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight #4E518B ΔE 0.022
- Dusk Blue #26538D ΔE 0.027
- Dusk #4E5481 ΔE 0.031
- Denim Blue #3B5B92 ΔE 0.031
- Light Navy Blue #2E5A88 ΔE 0.034
- Light Navy #155084 ΔE 0.043
- Dusky Blue #475F94 ΔE 0.046
- Cobalt #1E488F ΔE 0.047
Use #3F508B 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.