#3973B2
Closest named color: Flat Blue (#3C73A8). oklch(54.7% 0.116 252.4), rgb(57, 115, 178).
Aa
White text reads best on this color (4.91:1).
About this color
#3973B2 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.116 and its hue 252°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.016 away. White text reads best on it, at 4.91:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.116) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.26:1 |
| White text | 4.91:1 |
Values
| HEX | #3973B2 |
| RGB | rgb(57, 115, 178) |
| HSL | hsl(211, 51%, 46%) |
| OKLCH | oklch(54.7% 0.116 252.4) |
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 #3973B2 | 4.91:1 | AA | Lc -79.2 | Fine for body text |
| Black text on #3973B2 | 4.26:1 | AA large text | Lc 30.3 | Non-text elements, placeholder text |
| #3973B2 text on white | 4.91:1 | AA | Lc 73.8 | Content text, not long reading |
| #3973B2 text on black | 4.26:1 | AA large text | Lc -27.9 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E3EBF4
oklch(93.7% 0.015 251.2)
-
Step 200
200
#CCDBEC
oklch(88.5% 0.029 251.5)
-
Step 300
300
#A9C3E2
oklch(80.8% 0.052 253)
-
Step 400
400
#7BA4D4
oklch(70.7% 0.084 252.9)
-
Step 500
500
#588DC8
oklch(63.2% 0.106 252.2)
-
Step 600
600 (this color)
#3973B2
oklch(54.7% 0.116 252.4)
-
Step 700
700
#2E639C
oklch(49.2% 0.108 252.3)
-
Step 800
800
#27517E
oklch(42.7% 0.089 252)
-
Step 900
900
#244365
oklch(37.6% 0.069 252.1)
-
Step 950
950
#16283B
oklch(27.1% 0.043 250.9)
#3973B2 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) | #5777B5 | 0.035 |
| Deuteranopia (no green cones) | #466BB1 | 0.024 |
| Tritanopia (no blue cones) | #00828A | 0.091 |
| Achromatopsia (no color) | #707070 | 0.116 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3973B2
#3973B2
oklch(54.7% 0.116 252.4)
- #996402
#996402
oklch(54.7% 0.116 72.9)
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 #3973B2, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.016
- Windows Blue #3778BF ΔE 0.022
- French Blue #436BAD ΔE 0.023
- Nice Blue #107AB0 ΔE 0.028
- Muted Blue #3B719F ΔE 0.029
- Mid Blue #276AB3 ΔE 0.032
- Dull Blue #49759C ΔE 0.039
- Steel Blue #4682B4 ΔE 0.046
Use #3973B2 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.