#3F7BD9
Closest named color: Windows Blue (#3778BF). oklch(59.1% 0.157 259.1), rgb(63, 123, 217).
Aa
Black text reads best on this color (5.04:1).
About this color
#3F7BD9 is a medium-dark, vivid blue. In OKLCH its lightness is 59%, its chroma 0.157 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.041 away. Black text reads best on it, at 5.04:1.
| Hue family | Blues |
| Lightness | medium-dark (59%) |
| Chroma | vivid (0.157) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 5.04:1 |
| White text | 4.16:1 |
Values
| HEX | #3F7BD9 |
| RGB | rgb(63, 123, 217) |
| HSL | hsl(217, 67%, 55%) |
| OKLCH | oklch(59.1% 0.157 259.1) |
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 #3F7BD9 | 4.16:1 | AA large text | Lc -73.8 | Content text, not long reading |
| Black text on #3F7BD9 | 5.04:1 | AA | Lc 35.8 | Non-text elements, placeholder text |
| #3F7BD9 text on white | 4.16:1 | AA large text | Lc 68.3 | Content text, not long reading |
| #3F7BD9 text on black | 5.04:1 | AA | Lc -33.4 | 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
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E2EBF8
oklch(93.7% 0.02 257.5)
-
Step 200
200
#CADAF4
oklch(88.4% 0.04 260.1)
-
Step 300
300
#A6C2EF
oklch(80.9% 0.071 259.8)
-
Step 400
400
#75A1E7
oklch(70.6% 0.114 259.4)
-
Step 500
500
#5188E0
oklch(63% 0.145 259.4)
-
Step 600
600 (this color)
#3F7BD9
oklch(59.1% 0.157 259.1)
-
Step 700
700
#275DB2
oklch(49% 0.147 259.3)
-
Step 800
800
#224D90
oklch(42.8% 0.121 259.1)
-
Step 900
900
#214173
oklch(37.8% 0.094 259)
-
Step 950
950
#142643
oklch(27% 0.059 259.5)
#3F7BD9 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) | #4D84DD | 0.029 |
| Deuteranopia (no green cones) | #3176D7 | 0.019 |
| Tritanopia (no blue cones) | #00919F | 0.125 |
| Achromatopsia (no color) | #7C7C7C | 0.157 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F7BD9
#3F7BD9
oklch(59.1% 0.157 259.1)
- #A47300
#A47300
oklch(59% 0.123 79)
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 #3F7BD9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.041
- Water Blue #0E87CC ΔE 0.046
- Royal Blue #4169E1 ΔE 0.049
- Dark Sky Blue #448EE4 ΔE 0.052
- Clear Blue #247AFD ΔE 0.056
- Cerulean Blue #056EEE ΔE 0.059
- Soft Blue #6488EA ΔE 0.059
- Cool Blue #4984B8 ΔE 0.062
Use #3F7BD9 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.