#3971CA
Closest named color: Windows Blue (#3778BF). oklch(55.7% 0.15 259.3), rgb(57, 113, 202).
Aa
White text reads best on this color (4.78:1).
About this color
#3971CA is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.150 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.028 away. White text reads best on it, at 4.78:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.150) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.38:1 |
| White text | 4.78:1 |
Values
| HEX | #3971CA |
| RGB | rgb(57, 113, 202) |
| HSL | hsl(217, 58%, 51%) |
| OKLCH | oklch(55.7% 0.15 259.3) |
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 #3971CA | 4.78:1 | AA | Lc -78.3 | Fine for body text |
| Black text on #3971CA | 4.38:1 | AA large text | Lc 31.2 | Non-text elements, placeholder text |
| #3971CA text on white | 4.78:1 | AA | Lc 72.9 | Content text, not long reading |
| #3971CA text on black | 4.38:1 | AA large text | Lc -28.8 | 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
#E2EAF7
oklch(93.5% 0.02 260.2)
-
Step 200
200
#CBDAF3
oklch(88.5% 0.038 260.7)
-
Step 300
300
#A7C2ED
oklch(80.9% 0.068 259.6)
-
Step 400
400
#78A1E4
oklch(70.6% 0.109 259.9)
-
Step 500
500
#5489DC
oklch(63.2% 0.138 259)
-
Step 600
600 (this color)
#3971CA
oklch(55.7% 0.15 259.3)
-
Step 700
700
#2B5EAE
oklch(49.1% 0.139 259.2)
-
Step 800
800
#254D8D
oklch(42.7% 0.115 259.4)
-
Step 900
900
#234171
oklch(37.8% 0.09 259.4)
-
Step 950
950
#152642
oklch(27% 0.057 259.9)
#3971CA 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) | #457ACD | 0.028 |
| Deuteranopia (no green cones) | #296CC8 | 0.020 |
| Tritanopia (no blue cones) | #008693 | 0.120 |
| Achromatopsia (no color) | #727272 | 0.150 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3971CA
#3971CA
oklch(55.7% 0.15 259.3)
- #976A00
#976A00
oklch(55.7% 0.116 79.3)
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 #3971CA, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.028
- Mid Blue #276AB3 ΔE 0.043
- Royal Blue #4169E1 ΔE 0.043
- French Blue #436BAD ΔE 0.045
- Flat Blue #3C73A8 ΔE 0.055
- Nice Blue #107AB0 ΔE 0.056
- Water Blue #0E87CC ΔE 0.060
- Cerulean Blue #056EEE ΔE 0.061
Use #3971CA 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.