#3F63CB
Closest named color: Royal Blue (#4169E1). oklch(53.1% 0.167 266.4), rgb(63, 99, 203).
Aa
White text reads best on this color (5.44:1).
About this color
#3F63CB is a medium-dark, vivid blue. In OKLCH its lightness is 53%, its chroma 0.167 and its hue 266°. 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 5.44:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | vivid (0.167) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 3.85:1 |
| White text | 5.44:1 |
Values
| HEX | #3F63CB |
| RGB | rgb(63, 99, 203) |
| HSL | hsl(225, 57%, 52%) |
| OKLCH | oklch(53.1% 0.167 266.4) |
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 #3F63CB | 5.44:1 | AA | Lc -82.1 | Fine for body text |
| Black text on #3F63CB | 3.85:1 | AA large text | Lc 27.3 | Dividers and decoration only |
| #3F63CB text on white | 5.44:1 | AA | Lc 76.8 | Fine for body text |
| #3F63CB text on black | 3.85:1 | AA large text | Lc -25.0 | 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
#F2F5FC
oklch(97% 0.01 267.4)
-
Step 100
100
#E3EAF9
oklch(93.6% 0.022 265.8)
-
Step 200
200
#CCD9F6
oklch(88.5% 0.042 266.3)
-
Step 300
300
#AAC0F2
oklch(80.9% 0.075 266.2)
-
Step 400
400
#7E9EEC
oklch(70.8% 0.12 266.4)
-
Step 500
500
#5E84E6
oklch(63.2% 0.153 266.2)
-
Step 600
600 (this color)
#3F63CB
oklch(53.1% 0.167 266.4)
-
Step 700
700
#3858B7
oklch(49% 0.155 266.6)
-
Step 800
800
#2E4994
oklch(42.7% 0.128 266.2)
-
Step 900
900
#293E76
oklch(37.8% 0.099 266.3)
-
Step 950
950
#182545
oklch(27.1% 0.062 265.8)
#3F63CB 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) | #2370CF | 0.036 |
| Deuteranopia (no green cones) | #0064C9 | 0.036 |
| Tritanopia (no blue cones) | #007C8D | 0.137 |
| Achromatopsia (no color) | #6A6A6A | 0.167 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F63CB
#3F63CB
oklch(53.1% 0.167 266.4)
- #876600
#876600
oklch(52.9% 0.108 86.3)
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 #3F63CB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.036
- Warm Blue #4B57DB ΔE 0.040
- Mid Blue #276AB3 ΔE 0.049
- Iris #6258C4 ΔE 0.049
- Dark Periwinkle #665FD1 ΔE 0.051
- Neon Blue #4361EE ΔE 0.054
- French Blue #436BAD ΔE 0.055
- Slate Blue #6A5ACD ΔE 0.058
Use #3F63CB 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.