#3866CB
Closest named color: Royal Blue (#4169E1). oklch(53.4% 0.165 263.4), rgb(56, 102, 203).
Aa
White text reads best on this color (5.34:1).
About this color
#3866CB is a medium-dark, vivid blue. In OKLCH its lightness is 53%, its chroma 0.165 and its hue 263°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.036 away. White text reads best on it, at 5.34:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | vivid (0.165) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 3.93:1 |
| White text | 5.34:1 |
Values
| HEX | #3866CB |
| RGB | rgb(56, 102, 203) |
| HSL | hsl(221, 59%, 51%) |
| OKLCH | oklch(53.4% 0.165 263.4) |
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 #3866CB | 5.34:1 | AA | Lc -81.5 | Fine for body text |
| Black text on #3866CB | 3.93:1 | AA large text | Lc 27.9 | Dividers and decoration only |
| #3866CB text on white | 5.34:1 | AA | Lc 76.2 | Fine for body text |
| #3866CB text on black | 3.93:1 | AA large text | Lc -25.5 | 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 600.
-
Step 50
50
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E2EAF9
oklch(93.5% 0.022 263.2)
-
Step 200
200
#CBDAF5
oklch(88.6% 0.041 262.3)
-
Step 300
300
#A8C1F1
oklch(80.9% 0.074 263.3)
-
Step 400
400
#7A9FEB
oklch(70.7% 0.119 263.8)
-
Step 500
500
#5885E5
oklch(63% 0.153 263.7)
-
Step 600
600 (this color)
#3866CB
oklch(53.4% 0.165 263.4)
-
Step 700
700
#305AB6
oklch(49% 0.153 263.4)
-
Step 800
800
#294A94
oklch(42.7% 0.128 263.8)
-
Step 900
900
#253F76
oklch(37.8% 0.099 263.4)
-
Step 950
950
#162545
oklch(27% 0.063 263.8)
#3866CB 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) | #2A72CF | 0.031 |
| Deuteranopia (no green cones) | #0064C9 | 0.031 |
| Tritanopia (no blue cones) | #007E8F | 0.131 |
| Achromatopsia (no color) | #6B6B6B | 0.165 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3866CB
#3866CB
oklch(53.4% 0.165 263.4)
- #8B6600
#8B6600
oklch(53.4% 0.11 83.5)
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 #3866CB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.036
- Mid Blue #276AB3 ΔE 0.043
- Warm Blue #4B57DB ΔE 0.047
- French Blue #436BAD ΔE 0.052
- Windows Blue #3778BF ΔE 0.055
- Neon Blue #4361EE ΔE 0.057
- Dark Periwinkle #665FD1 ΔE 0.057
- Iris #6258C4 ΔE 0.057
Use #3866CB 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.