#3F65CB
Closest named color: Royal Blue (#4169E1). oklch(53.5% 0.164 265.7), rgb(63, 101, 203).
Aa
White text reads best on this color (5.33:1).
About this color
#3F65CB is a medium-dark, vivid blue. In OKLCH its lightness is 53%, its chroma 0.164 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.035 away. White text reads best on it, at 5.33:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | vivid (0.164) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 3.93:1 |
| White text | 5.33:1 |
Values
| HEX | #3F65CB |
| RGB | rgb(63, 101, 203) |
| HSL | hsl(224, 57%, 52%) |
| OKLCH | oklch(53.5% 0.164 265.7) |
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 #3F65CB | 5.33:1 | AA | Lc -81.5 | Fine for body text |
| Black text on #3F65CB | 3.93:1 | AA large text | Lc 27.9 | Dividers and decoration only |
| #3F65CB text on white | 5.33:1 | AA | Lc 76.2 | Fine for body text |
| #3F65CB 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
#F2F5FC
oklch(97% 0.01 267.4)
-
Step 100
100
#E3EAF9
oklch(93.6% 0.022 265.8)
-
Step 200
200
#CCD9F5
oklch(88.4% 0.041 265.7)
-
Step 300
300
#AAC0F1
oklch(80.8% 0.074 265.9)
-
Step 400
400
#7D9EEB
oklch(70.6% 0.119 265.8)
-
Step 500
500
#5D84E4
oklch(63% 0.151 265.6)
-
Step 600
600 (this color)
#3F65CB
oklch(53.5% 0.164 265.7)
-
Step 700
700
#3759B6
oklch(49.1% 0.153 265.9)
-
Step 800
800
#2D4993
oklch(42.6% 0.126 265.7)
-
Step 900
900
#283E75
oklch(37.6% 0.098 265.5)
-
Step 950
950
#182545
oklch(27.1% 0.062 265.8)
#3F65CB 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) | #2972CF | 0.035 |
| Deuteranopia (no green cones) | #0065C9 | 0.036 |
| Tritanopia (no blue cones) | #007D8E | 0.134 |
| Achromatopsia (no color) | #6B6B6B | 0.164 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F65CB
#3F65CB
oklch(53.5% 0.164 265.7)
- #896700
#896700
oklch(53.4% 0.109 85.8)
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 #3F65CB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.035
- Warm Blue #4B57DB ΔE 0.044
- Mid Blue #276AB3 ΔE 0.047
- Dark Periwinkle #665FD1 ΔE 0.051
- Iris #6258C4 ΔE 0.051
- French Blue #436BAD ΔE 0.052
- Neon Blue #4361EE ΔE 0.055
- Windows Blue #3778BF ΔE 0.057
Use #3F65CB 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.