#3F78BD
Closest named color: Windows Blue (#3778BF). oklch(56.7% 0.123 254.5), rgb(63, 120, 189).
Aa
Black text reads best on this color (4.63:1).
About this color
#3F78BD is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.123 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.007 away. Black text reads best on it, at 4.63:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.123) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.63:1 |
| White text | 4.53:1 |
Values
| HEX | #3F78BD |
| RGB | rgb(63, 120, 189) |
| HSL | hsl(213, 50%, 49%) |
| OKLCH | oklch(56.7% 0.123 254.5) |
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 #3F78BD | 4.53:1 | AA | Lc -76.7 | Fine for body text |
| Black text on #3F78BD | 4.63:1 | AA | Lc 32.9 | Non-text elements, placeholder text |
| #3F78BD text on white | 4.53:1 | AA | Lc 71.2 | Content text, not long reading |
| #3F78BD text on black | 4.63:1 | AA | Lc -30.4 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E3EBF5
oklch(93.7% 0.016 253.9)
-
Step 200
200
#CCDBEE
oklch(88.6% 0.031 254.3)
-
Step 300
300
#A9C3E4
oklch(80.9% 0.055 254.5)
-
Step 400
400
#7AA3D7
oklch(70.6% 0.089 254.7)
-
Step 500
500
#578CCD
oklch(63.1% 0.114 254.3)
-
Step 600
600 (this color)
#3F78BD
oklch(56.7% 0.123 254.5)
-
Step 700
700
#2E62A0
oklch(49.2% 0.114 254.4)
-
Step 800
800
#275082
oklch(42.7% 0.095 254.7)
-
Step 900
900
#244368
oklch(37.8% 0.074 253.9)
-
Step 950
950
#16273D
oklch(27% 0.047 255.4)
#3F78BD 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) | #597DC0 | 0.032 |
| Deuteranopia (no green cones) | #4771BC | 0.019 |
| Tritanopia (no blue cones) | #008891 | 0.099 |
| Achromatopsia (no color) | #767676 | 0.123 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F78BD
#3F78BD
oklch(56.7% 0.123 254.5)
- #9F6A00
#9F6A00
oklch(56.6% 0.12 74.6)
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 #3F78BD, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.007
- Flat Blue #3C73A8 ΔE 0.034
- Steel Blue #4682B4 ΔE 0.036
- Nice Blue #107AB0 ΔE 0.036
- Cool Blue #4984B8 ΔE 0.039
- French Blue #436BAD ΔE 0.040
- Water Blue #0E87CC ΔE 0.045
- Mid Blue #276AB3 ΔE 0.048
Use #3F78BD 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.