#3F7DBF
Closest named color: Windows Blue (#3778BF). oklch(57.9% 0.121 251.9), rgb(63, 125, 191).
Aa
Black text reads best on this color (4.89:1).
About this color
#3F7DBF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 58%, its chroma 0.121 and its hue 252°. 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 4.89:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | moderately saturated (0.121) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.89:1 |
| White text | 4.28:1 |
Values
| HEX | #3F7DBF |
| RGB | rgb(63, 125, 191) |
| HSL | hsl(211, 50%, 50%) |
| OKLCH | oklch(57.9% 0.121 251.9) |
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 #3F7DBF | 4.28:1 | AA large text | Lc -74.9 | Content text, not long reading |
| Black text on #3F7DBF | 4.89:1 | AA | Lc 34.7 | Non-text elements, placeholder text |
| #3F7DBF text on white | 4.28:1 | AA large text | Lc 69.4 | Content text, not long reading |
| #3F7DBF text on black | 4.89:1 | AA | Lc -32.3 | 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
#CBDBED
oklch(88.5% 0.03 251.3)
-
Step 300
300
#A8C4E3
oklch(81% 0.053 251.1)
-
Step 400
400
#78A4D6
oklch(70.6% 0.088 252.2)
-
Step 500
500
#558DCB
oklch(63.2% 0.111 252.2)
-
Step 600
600 (this color)
#3F7DBF
oklch(57.9% 0.121 251.9)
-
Step 700
700
#2A639E
oklch(49.2% 0.112 251.8)
-
Step 800
800
#245180
oklch(42.7% 0.093 251.7)
-
Step 900
900
#224367
oklch(37.6% 0.073 252.1)
-
Step 950
950
#15283C
oklch(27.1% 0.045 250.9)
#3F7DBF 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) | #6081C2 | 0.038 |
| Deuteranopia (no green cones) | #4E75BE | 0.024 |
| Tritanopia (no blue cones) | #008C95 | 0.094 |
| Achromatopsia (no color) | #7A7A7A | 0.121 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F7DBF
#3F7DBF
oklch(57.9% 0.121 251.9)
- #A56C0C
#A56C0C
oklch(57.8% 0.121 71.9)
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 #3F7DBF, 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 0.026
- Cool Blue #4984B8 ΔE 0.027
- Water Blue #0E87CC ΔE 0.035
- Nice Blue #107AB0 ΔE 0.039
- Flat Blue #3C73A8 ΔE 0.042
- Off Blue #5684AE ΔE 0.044
- Blue NCS #118AB2 ΔE 0.051
Use #3F7DBF 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.