#3F7BB8
Closest named color: Windows Blue (#3778BF). oklch(57.1% 0.114 250.8), rgb(63, 123, 184).
Aa
Black text reads best on this color (4.73:1).
About this color
#3F7BB8 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.114 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.017 away. Black text reads best on it, at 4.73:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.114) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.73:1 |
| White text | 4.43:1 |
Values
| HEX | #3F7BB8 |
| RGB | rgb(63, 123, 184) |
| HSL | hsl(210, 49%, 48%) |
| OKLCH | oklch(57.1% 0.114 250.8) |
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 #3F7BB8 | 4.43:1 | AA large text | Lc -76.0 | Fine for body text |
| Black text on #3F7BB8 | 4.73:1 | AA | Lc 33.6 | Non-text elements, placeholder text |
| #3F7BB8 text on white | 4.43:1 | AA large text | Lc 70.5 | Content text, not long reading |
| #3F7BB8 text on black | 4.73:1 | AA | Lc -31.1 | 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
#E3EBF4
oklch(93.7% 0.015 251.2)
-
Step 200
200
#CCDBEC
oklch(88.5% 0.029 251.5)
-
Step 300
300
#A9C4E1
oklch(81% 0.051 250.3)
-
Step 400
400
#7AA5D2
oklch(70.8% 0.081 250.1)
-
Step 500
500
#578DC7
oklch(63.1% 0.105 251.4)
-
Step 600
600 (this color)
#3F7BB8
oklch(57.1% 0.114 250.8)
-
Step 700
700
#2C639A
oklch(49% 0.106 250.9)
-
Step 800
800
#26517D
oklch(42.6% 0.088 251.1)
-
Step 900
900
#244464
oklch(37.8% 0.067 250)
-
Step 950
950
#16283B
oklch(27.1% 0.043 250.9)
#3F7BB8 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) | #607EBB | 0.037 |
| Deuteranopia (no green cones) | #5072B7 | 0.028 |
| Tritanopia (no blue cones) | #008991 | 0.088 |
| Achromatopsia (no color) | #787878 | 0.114 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F7BB8
#3F7BB8
oklch(57.1% 0.114 250.8)
- #A16A1A
#A16A1A
oklch(57% 0.113 70.5)
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 #3F7BB8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.017
- Steel Blue #4682B4 ΔE 0.024
- Cool Blue #4984B8 ΔE 0.029
- Flat Blue #3C73A8 ΔE 0.031
- Nice Blue #107AB0 ΔE 0.031
- Off Blue #5684AE ΔE 0.042
- Water Blue #0E87CC ΔE 0.043
- Cerulean #457B9D ΔE 0.043
Use #3F7BB8 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.