#3F75B5
Closest named color: Windows Blue (#3778BF). oklch(55.5% 0.116 254), rgb(63, 117, 181).
Aa
White text reads best on this color (4.74:1).
About this color
#3F75B5 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.116 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.016 away. White text reads best on it, at 4.74:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.116) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.42:1 |
| White text | 4.74:1 |
Values
| HEX | #3F75B5 |
| RGB | rgb(63, 117, 181) |
| HSL | hsl(213, 48%, 48%) |
| OKLCH | oklch(55.5% 0.116 254) |
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 #3F75B5 | 4.74:1 | AA | Lc -78.2 | Fine for body text |
| Black text on #3F75B5 | 4.42:1 | AA large text | Lc 31.3 | Non-text elements, placeholder text |
| #3F75B5 text on white | 4.74:1 | AA | Lc 72.7 | Content text, not long reading |
| #3F75B5 text on black | 4.42:1 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E3EBF4
oklch(93.7% 0.015 251.2)
-
Step 200
200
#CCDBEC
oklch(88.5% 0.029 251.5)
-
Step 300
300
#AAC3E2
oklch(80.9% 0.052 253.9)
-
Step 400
400
#7CA4D4
oklch(70.8% 0.083 253.4)
-
Step 500
500
#5A8CC8
oklch(63% 0.106 253.8)
-
Step 600
600 (this color)
#3F75B5
oklch(55.5% 0.116 254)
-
Step 700
700
#31629C
oklch(49.1% 0.108 254.1)
-
Step 800
800
#29507E
oklch(42.6% 0.089 253.9)
-
Step 900
900
#264366
oklch(37.8% 0.07 254.1)
-
Step 950
950
#17273B
oklch(26.9% 0.043 254.6)
#3F75B5 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) | #5979B8 | 0.032 |
| Deuteranopia (no green cones) | #496EB4 | 0.020 |
| Tritanopia (no blue cones) | #00848C | 0.094 |
| Achromatopsia (no color) | #737373 | 0.116 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F75B5
#3F75B5
oklch(55.5% 0.116 254)
- #9B6707
#9B6707
oklch(55.6% 0.116 73.8)
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 #3F75B5, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.016
- Flat Blue #3C73A8 ΔE 0.021
- French Blue #436BAD ΔE 0.028
- Nice Blue #107AB0 ΔE 0.031
- Muted Blue #3B719F ΔE 0.035
- Steel Blue #4682B4 ΔE 0.039
- Mid Blue #276AB3 ΔE 0.040
- Dull Blue #49759C ΔE 0.040
Use #3F75B5 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.