#3F66F1
Closest named color: Neon Blue (#4361EE). oklch(56.6% 0.213 267.2), rgb(63, 102, 241).
Aa
White text reads best on this color (4.79:1).
About this color
#3F66F1 is a medium-dark, vivid blue. In OKLCH its lightness is 57%, its chroma 0.213 and its hue 267°. Its hue sits on the cool side of the wheel. The nearest named color is Neon Blue (#4361EE), ΔE 0.012 away. White text reads best on it, at 4.79:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | vivid (0.213) |
| Temperature | cool |
| Nearest name | Neon Blue (#4361EE) |
| Black text | 4.38:1 |
| White text | 4.79:1 |
Values
| HEX | #3F66F1 |
| RGB | rgb(63, 102, 241) |
| HSL | hsl(227, 86%, 60%) |
| OKLCH | oklch(56.6% 0.213 267.2) |
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 #3F66F1 | 4.79:1 | AA | Lc -78.1 | Fine for body text |
| Black text on #3F66F1 | 4.38:1 | AA large text | Lc 31.4 | Non-text elements, placeholder text |
| #3F66F1 text on white | 4.79:1 | AA | Lc 72.7 | Content text, not long reading |
| #3F66F1 text on black | 4.38:1 | AA large text | Lc -29.0 | 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
#F1F5FE
oklch(97% 0.013 266.7)
-
Step 100
100
#E1EAFD
oklch(93.6% 0.028 265.4)
-
Step 200
200
#C9D9FD
oklch(88.5% 0.053 266.4)
-
Step 300
300
#A5BFFF
oklch(80.9% 0.095 267.2)
-
Step 400
400
#769BFF
oklch(70.7% 0.152 267.2)
-
Step 500
500
#557EFE
oklch(63.1% 0.196 267.2)
-
Step 600
600 (this color)
#3F66F1
oklch(56.6% 0.213 267.2)
-
Step 700
700
#3051CF
oklch(49.2% 0.198 267.2)
-
Step 800
800
#2743A7
oklch(42.7% 0.164 267)
-
Step 900
900
#233A84
oklch(37.6% 0.128 267)
-
Step 950
950
#15234D
oklch(27% 0.08 267.1)
#3F66F1 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) | #007BF6 | 0.052 |
| Deuteranopia (no green cones) | #006AEE | 0.032 |
| Tritanopia (no blue cones) | #0089A2 | 0.168 |
| Achromatopsia (no color) | #727272 | 0.214 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F66F1
#3F66F1
oklch(56.6% 0.213 267.2)
- #937100
#937100
oklch(56.6% 0.116 87.6)
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 #3F66F1, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Neon Blue #4361EE ΔE 0.012
- Royal Blue #4169E1 ΔE 0.026
- Cerulean Blue #056EEE ΔE 0.033
- Bright Blue #0165FC ΔE 0.036
- Azul #1D5DEC ΔE 0.038
- Warm Blue #4B57DB ΔE 0.047
- Clear Blue #247AFD ΔE 0.049
- Electric Blue #0652FF ΔE 0.064
Use #3F66F1 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.