#3F78C8
Closest named color: Windows Blue (#3778BF). oklch(57.3% 0.138 257.3), rgb(63, 120, 200).
Aa
Black text reads best on this color (4.73:1).
About this color
#3F78C8 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.138 and its hue 257°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.016 away. Black text reads best on it, at 4.73:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.138) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.73:1 |
| White text | 4.43:1 |
Values
| HEX | #3F78C8 |
| RGB | rgb(63, 120, 200) |
| HSL | hsl(215, 55%, 52%) |
| OKLCH | oklch(57.3% 0.138 257.3) |
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 #3F78C8 | 4.43:1 | AA large text | Lc -76.0 | Fine for body text |
| Black text on #3F78C8 | 4.73:1 | AA | Lc 33.6 | Non-text elements, placeholder text |
| #3F78C8 text on white | 4.43:1 | AA large text | Lc 70.5 | Content text, not long reading |
| #3F78C8 text on black | 4.73:1 | AA | Lc -31.2 | Non-text elements, placeholder text |
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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF6
oklch(93.7% 0.018 253.3)
-
Step 200
200
#CBDAF0
oklch(88.4% 0.034 257.9)
-
Step 300
300
#A8C3E9
oklch(81% 0.061 256.9)
-
Step 400
400
#79A2DE
oklch(70.6% 0.099 257.8)
-
Step 500
500
#568AD5
oklch(63.1% 0.127 257.6)
-
Step 600
600 (this color)
#3F78C8
oklch(57.3% 0.138 257.3)
-
Step 700
700
#2C60A8
oklch(49.2% 0.128 257.2)
-
Step 800
800
#264E88
oklch(42.6% 0.107 257.9)
-
Step 900
900
#23426D
oklch(37.8% 0.083 257)
-
Step 950
950
#152740
oklch(27.1% 0.053 256.9)
#3F78C8 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) | #537FCB | 0.030 |
| Deuteranopia (no green cones) | #3E72C6 | 0.016 |
| Tritanopia (no blue cones) | #008B96 | 0.111 |
| Achromatopsia (no color) | #787878 | 0.138 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F78C8
#3F78C8
oklch(57.3% 0.138 257.3)
- #9F6D00
#9F6D00
oklch(57.2% 0.12 77)
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 #3F78C8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.016
- Water Blue #0E87CC ΔE 0.043
- Steel Blue #4682B4 ΔE 0.047
- Cool Blue #4984B8 ΔE 0.048
- Nice Blue #107AB0 ΔE 0.049
- French Blue #436BAD ΔE 0.050
- Flat Blue #3C73A8 ΔE 0.050
- Mid Blue #276AB3 ΔE 0.054
Use #3F78C8 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.