#3F73BF
Closest named color: Windows Blue (#3778BF). oklch(55.7% 0.131 257.9), rgb(63, 115, 191).
Aa
White text reads best on this color (4.75:1).
About this color
#3F73BF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.131 and its hue 258°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.014 away. White text reads best on it, at 4.75:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.131) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.41:1 |
| White text | 4.75:1 |
Values
| HEX | #3F73BF |
| RGB | rgb(63, 115, 191) |
| HSL | hsl(216, 50%, 50%) |
| OKLCH | oklch(55.7% 0.131 257.9) |
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 #3F73BF | 4.75:1 | AA | Lc -78.2 | Fine for body text |
| Black text on #3F73BF | 4.41:1 | AA large text | Lc 31.3 | Non-text elements, placeholder text |
| #3F73BF text on white | 4.75:1 | AA | Lc 72.7 | Content text, not long reading |
| #3F73BF text on black | 4.41:1 | AA large text | Lc -28.9 | 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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E3EAF6
oklch(93.5% 0.018 261.3)
-
Step 200
200
#CCDAEF
oklch(88.4% 0.033 258.4)
-
Step 300
300
#A9C2E7
oklch(80.8% 0.059 258.1)
-
Step 400
400
#7BA2DB
oklch(70.6% 0.094 257.8)
-
Step 500
500
#5A8AD2
oklch(63.1% 0.121 258.3)
-
Step 600
600 (this color)
#3F73BF
oklch(55.7% 0.131 257.9)
-
Step 700
700
#3160A5
oklch(49.2% 0.122 258.1)
-
Step 800
800
#294F85
oklch(42.8% 0.1 257.4)
-
Step 900
900
#26426B
oklch(37.8% 0.078 257.9)
-
Step 950
950
#16273F
oklch(27.1% 0.05 257.1)
#3F73BF 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) | #5179C2 | 0.027 |
| Deuteranopia (no green cones) | #3D6DBD | 0.017 |
| Tritanopia (no blue cones) | #008490 | 0.104 |
| Achromatopsia (no color) | #737373 | 0.131 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F73BF
#3F73BF
oklch(55.7% 0.131 257.9)
- #986900
#986900
oklch(55.6% 0.116 77.9)
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 #3F73BF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.014
- French Blue #436BAD ΔE 0.032
- Flat Blue #3C73A8 ΔE 0.037
- Mid Blue #276AB3 ΔE 0.038
- Nice Blue #107AB0 ΔE 0.043
- Muted Blue #3B719F ΔE 0.051
- Steel Blue #4682B4 ΔE 0.051
- Cool Blue #4984B8 ΔE 0.054
Use #3F73BF 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.