#3F66AF
Closest named color: French Blue (#436BAD). oklch(51.8% 0.124 261.8), rgb(63, 102, 175).
Aa
White text reads best on this color (5.62:1).
About this color
#3F66AF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 52%, its chroma 0.124 and its hue 262°. Its hue sits on the cool side of the wheel. The nearest named color is French Blue (#436BAD), ΔE 0.016 away. White text reads best on it, at 5.62:1.
| Hue family | Blues |
| Lightness | medium-dark (52%) |
| Chroma | moderately saturated (0.124) |
| Temperature | cool |
| Nearest name | French Blue (#436BAD) |
| Black text | 3.73:1 |
| White text | 5.62:1 |
Values
| HEX | #3F66AF |
| RGB | rgb(63, 102, 175) |
| HSL | hsl(219, 47%, 47%) |
| OKLCH | oklch(51.8% 0.124 261.8) |
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 #3F66AF | 5.62:1 | AA | Lc -83.2 | Fine for body text |
| Black text on #3F66AF | 3.73:1 | AA large text | Lc 26.2 | Dividers and decoration only |
| #3F66AF text on white | 5.62:1 | AA | Lc 77.9 | Fine for body text |
| #3F66AF text on black | 3.73:1 | AA large text | Lc -23.9 | 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 700.
-
Step 50
50
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E4EAF6
oklch(93.6% 0.017 264.5)
-
Step 200
200
#CDDAF0
oklch(88.5% 0.033 261)
-
Step 300
300
#ACC1E8
oklch(80.8% 0.06 262.8)
-
Step 400
400
#7FA1DD
oklch(70.7% 0.096 261.4)
-
Step 500
500
#5F88D3
oklch(63% 0.123 261.7)
-
Step 600
600
#4671C1
oklch(55.7% 0.134 261.7)
-
Step 700
700 (this color)
#3F66AF
oklch(51.8% 0.124 261.8)
-
Step 800
800
#2E4D87
oklch(42.7% 0.103 261.8)
-
Step 900
900
#29416C
oklch(37.8% 0.08 261.3)
-
Step 950
950
#18263F
oklch(27% 0.051 261.4)
#3F66AF 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) | #456DB2 | 0.022 |
| Deuteranopia (no green cones) | #3463AD | 0.015 |
| Tritanopia (no blue cones) | #007782 | 0.104 |
| Achromatopsia (no color) | #676767 | 0.124 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F66AF
#3F66AF
oklch(51.8% 0.124 261.8)
- #876100
#876100
oklch(51.8% 0.107 81.8)
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 #3F66AF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- French Blue #436BAD ΔE 0.016
- Mid Blue #276AB3 ΔE 0.021
- Flat Blue #3C73A8 ΔE 0.041
- Dusky Blue #475F94 ΔE 0.044
- Muted Blue #3B719F ΔE 0.045
- Windows Blue #3778BF ΔE 0.051
- Denim Blue #3B5B92 ΔE 0.052
- Denim #3B638C ΔE 0.056
Use #3F66AF 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.