#3B66CF
Closest named color: Royal Blue (#4169E1). oklch(53.8% 0.17 264.6), rgb(59, 102, 207).
Aa
White text reads best on this color (5.26:1).
About this color
#3B66CF is a medium-dark, vivid blue. In OKLCH its lightness is 54%, its chroma 0.170 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.029 away. White text reads best on it, at 5.26:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | vivid (0.170) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 3.98:1 |
| White text | 5.26:1 |
Values
| HEX | #3B66CF |
| RGB | rgb(59, 102, 207) |
| HSL | hsl(223, 61%, 52%) |
| OKLCH | oklch(53.8% 0.17 264.6) |
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 #3B66CF | 5.26:1 | AA | Lc -81.1 | Fine for body text |
| Black text on #3B66CF | 3.98:1 | AA large text | Lc 28.3 | Dividers and decoration only |
| #3B66CF text on white | 5.26:1 | AA | Lc 75.8 | Fine for body text |
| #3B66CF text on black | 3.98:1 | AA large text | Lc -26.0 | 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
#F2F5FD
oklch(97% 0.011 269.6)
-
Step 100
100
#E3EAF9
oklch(93.6% 0.022 265.8)
-
Step 200
200
#CBD9F6
oklch(88.4% 0.043 265)
-
Step 300
300
#A8C1F3
oklch(81% 0.076 264)
-
Step 400
400
#7A9FED
oklch(70.8% 0.122 264.2)
-
Step 500
500
#5984E7
oklch(63% 0.157 264.6)
-
Step 600
600 (this color)
#3B66CF
oklch(53.8% 0.17 264.6)
-
Step 700
700
#3259B9
oklch(49.1% 0.158 264.6)
-
Step 800
800
#2A4995
oklch(42.6% 0.13 264.7)
-
Step 900
900
#263E77
oklch(37.7% 0.102 264.8)
-
Step 950
950
#162546
oklch(27.1% 0.065 264.1)
#3B66CF 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) | #2573D3 | 0.034 |
| Deuteranopia (no green cones) | #0065CD | 0.032 |
| Tritanopia (no blue cones) | #007F91 | 0.135 |
| Achromatopsia (no color) | #6C6C6C | 0.170 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3B66CF
#3B66CF
oklch(53.8% 0.17 264.6)
- #8C6800
#8C6800
oklch(53.9% 0.111 84.6)
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 #3B66CF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.029
- Warm Blue #4B57DB ΔE 0.043
- Mid Blue #276AB3 ΔE 0.050
- Neon Blue #4361EE ΔE 0.050
- Cerulean Blue #056EEE ΔE 0.053
- Dark Periwinkle #665FD1 ΔE 0.053
- Azul #1D5DEC ΔE 0.056
- Iris #6258C4 ΔE 0.056
Use #3B66CF 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.