#3971AB
Closest named color: Flat Blue (#3C73A8). oklch(53.8% 0.109 251.2), rgb(57, 113, 171).
Aa
White text reads best on this color (5.09:1).
About this color
#3971AB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 54%, its chroma 0.109 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.009 away. White text reads best on it, at 5.09:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | moderately saturated (0.109) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.12:1 |
| White text | 5.09:1 |
Values
| HEX | #3971AB |
| RGB | rgb(57, 113, 171) |
| HSL | hsl(211, 50%, 45%) |
| OKLCH | oklch(53.8% 0.109 251.2) |
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 #3971AB | 5.09:1 | AA | Lc -80.3 | Fine for body text |
| Black text on #3971AB | 4.12:1 | AA large text | Lc 29.2 | Dividers and decoration only |
| #3971AB text on white | 5.09:1 | AA | Lc 74.9 | Content text, not long reading |
| #3971AB text on black | 4.12:1 | AA large text | Lc -26.8 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E3EBF3
oklch(93.6% 0.014 248)
-
Step 200
200
#CCDBEB
oklch(88.5% 0.027 249.9)
-
Step 300
300
#AAC3E0
oklch(80.8% 0.049 252.3)
-
Step 400
400
#7CA4D0
oklch(70.6% 0.078 251.3)
-
Step 500
500
#5A8DC4
oklch(63.1% 0.1 251.4)
-
Step 600
600 (this color)
#3971AB
oklch(53.8% 0.109 251.2)
-
Step 700
700
#306398
oklch(49% 0.102 251.4)
-
Step 800
800
#29517B
oklch(42.7% 0.084 251.4)
-
Step 900
900
#264363
oklch(37.6% 0.065 252.1)
-
Step 950
950
#17283A
oklch(27.1% 0.041 250.8)
#3971AB 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) | #5874AD | 0.036 |
| Deuteranopia (no green cones) | #4869AA | 0.025 |
| Tritanopia (no blue cones) | #007F86 | 0.086 |
| Achromatopsia (no color) | #6E6E6E | 0.109 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3971AB
#3971AB
oklch(53.8% 0.109 251.2)
- #956213
#956213
oklch(53.9% 0.109 71.5)
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 #3971AB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.009
- Muted Blue #3B719F ΔE 0.019
- French Blue #436BAD ΔE 0.019
- Nice Blue #107AB0 ΔE 0.030
- Mid Blue #276AB3 ΔE 0.031
- Dull Blue #49759C ΔE 0.033
- Windows Blue #3778BF ΔE 0.034
- Ocean Blue #03719C ΔE 0.039
Use #3971AB 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.