Windows Blue #3778BF
Windows Blue is a medium-dark, moderately saturated blue with hex code #3778BF and RGB rgb(55, 120, 191).
Aa
Black text reads best on this color (4.60:1).
About this color
#3778BF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.129 and its hue 253°. Its hue sits on the cool side of the wheel. It is the named color Windows Blue. Black text reads best on it, at 4.60:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.129) |
| Temperature | cool |
| Nearest name | Windows Blue |
| Black text | 4.60:1 |
| White text | 4.56:1 |
Colors that go with Windows Blue
Matches found by rotating Windows Blue around the OKLCH hue wheel, each labelled with the closest name in our list.
Complementary
The opposite hue (180°).
Analogous
Neighbouring hues, 30° either side.
Triadic
Three hues spaced 120° apart.
Color palettes with Windows Blue
Curated color palettes that contain a color within ΔE 0.06 (OKLab) of Windows Blue, closest first.
Similar named colors
The eight named colors closest to Windows Blue, with their ΔE distance.
- Nice Blue #107AB0 ΔE 0.034
- Flat Blue #3C73A8 ΔE 0.036
- Steel Blue #4682B4 ΔE 0.040
- French Blue #436BAD ΔE 0.041
- Water Blue #0E87CC ΔE 0.043
- Cool Blue #4984B8 ΔE 0.043
- Mid Blue #276AB3 ΔE 0.045
- Muted Blue #3B719F ΔE 0.050
More about Windows Blue
How to make Windows Blue
A starting recipe from common paint colors, found with a spectral paint model (the color mixer’s paint mode). Real pigments vary, so mix a small test batch and adjust.
- 2 parts blue
- 1 part white
- 1 part gray
Recipe result: #3B79BD, a difference of ΔE 0.006 from Windows Blue. That is very close: most people will not see the difference.
Codes for Windows Blue in every format
| HEX | #3778BF |
| RGB | rgb(55, 120, 191) |
| HSL | hsl(211, 55%, 48%) |
| OKLCH | oklch(56.5% 0.129 252.8) |
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 #3778BF | 4.56:1 | AA | Lc -76.9 | Fine for body text |
| Black text on #3778BF | 4.60:1 | AA | Lc 32.7 | Non-text elements, placeholder text |
| #3778BF text on white | 4.56:1 | AA | Lc 71.4 | Content text, not long reading |
| #3778BF text on black | 4.60:1 | AA | Lc -30.3 | Non-text elements, placeholder text |
Shades and tints of Windows Blue
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
#E2EBF5
oklch(93.6% 0.017 250.8)
-
Step 200
200
#CBDBEE
oklch(88.5% 0.031 252.7)
-
Step 300
300
#A7C4E6
oklch(81% 0.058 252.6)
-
Step 400
400
#76A4D9
oklch(70.6% 0.093 252.6)
-
Step 500
500
#528CCF
oklch(63% 0.119 253.2)
-
Step 600
600 (this color)
#3778BF
oklch(56.5% 0.129 252.8)
-
Step 700
700
#2662A2
oklch(49% 0.12 252.8)
-
Step 800
800
#215083
oklch(42.6% 0.099 252.8)
-
Step 900
900
#214369
oklch(37.7% 0.077 252.8)
-
Step 950
950
#14273E
oklch(26.9% 0.05 254.1)
Windows Blue 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) | #587DC2 | 0.037 |
| Deuteranopia (no green cones) | #4370BE | 0.023 |
| Tritanopia (no blue cones) | #008992 | 0.100 |
| Achromatopsia (no color) | #767676 | 0.129 |
Use Windows Blue 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.