#3F70CC
Closest named color: Windows Blue (#3778BF). oklch(55.9% 0.152 261.7), rgb(63, 112, 204).
Aa
White text reads best on this color (4.77:1).
About this color
#3F70CC is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.152 and its hue 262°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.033 away. White text reads best on it, at 4.77:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.152) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.40:1 |
| White text | 4.77:1 |
Values
| HEX | #3F70CC |
| RGB | rgb(63, 112, 204) |
| HSL | hsl(219, 58%, 52%) |
| OKLCH | oklch(55.9% 0.152 261.7) |
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 #3F70CC | 4.77:1 | AA | Lc -78.2 | Fine for body text |
| Black text on #3F70CC | 4.40:1 | AA large text | Lc 31.3 | Non-text elements, placeholder text |
| #3F70CC text on white | 4.77:1 | AA | Lc 72.8 | Content text, not long reading |
| #3F70CC text on black | 4.40:1 | 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
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E3EAF8
oklch(93.6% 0.02 264.5)
-
Step 200
200
#CBDAF3
oklch(88.5% 0.038 260.7)
-
Step 300
300
#A8C1EE
oklch(80.8% 0.07 262.1)
-
Step 400
400
#7AA0E5
oklch(70.6% 0.11 261.8)
-
Step 500
500
#5987DD
oklch(63% 0.14 261.9)
-
Step 600
600 (this color)
#3F70CC
oklch(55.9% 0.152 261.7)
-
Step 700
700
#305DB0
oklch(49.2% 0.141 261.4)
-
Step 800
800
#294C8E
oklch(42.7% 0.117 261.7)
-
Step 900
900
#254072
oklch(37.7% 0.092 261.6)
-
Step 950
950
#162642
oklch(27% 0.057 260.9)
#3F70CC 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) | #427ACF | 0.027 |
| Deuteranopia (no green cones) | #276DCA | 0.022 |
| Tritanopia (no blue cones) | #008594 | 0.122 |
| Achromatopsia (no color) | #737373 | 0.152 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F70CC
#3F70CC
oklch(55.9% 0.152 261.7)
- #966C00
#966C00
oklch(55.9% 0.115 81.6)
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 #3F70CC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.033
- Royal Blue #4169E1 ΔE 0.039
- Mid Blue #276AB3 ΔE 0.048
- French Blue #436BAD ΔE 0.048
- Flat Blue #3C73A8 ΔE 0.059
- Cerulean Blue #056EEE ΔE 0.059
- Dark Periwinkle #665FD1 ΔE 0.060
- Nice Blue #107AB0 ΔE 0.062
Use #3F70CC 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.