#3173AF
Closest named color: Flat Blue (#3C73A8). oklch(54.2% 0.115 249), rgb(49, 115, 175).
Aa
White text reads best on this color (4.99:1).
About this color
#3173AF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 54%, its chroma 0.115 and its hue 249°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.014 away. White text reads best on it, at 4.99:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | moderately saturated (0.115) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.20:1 |
| White text | 4.99:1 |
Values
| HEX | #3173AF |
| RGB | rgb(49, 115, 175) |
| HSL | hsl(209, 56%, 44%) |
| OKLCH | oklch(54.2% 0.115 249) |
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 #3173AF | 4.99:1 | AA | Lc -79.7 | Fine for body text |
| Black text on #3173AF | 4.20:1 | AA large text | Lc 29.8 | Dividers and decoration only |
| #3173AF text on white | 4.99:1 | AA | Lc 74.3 | Content text, not long reading |
| #3173AF text on black | 4.20:1 | AA large text | Lc -27.4 | 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
#E2EBF4
oklch(93.6% 0.016 248)
-
Step 200
200
#CBDBEC
oklch(88.5% 0.029 249.8)
-
Step 300
300
#A7C4E1
oklch(80.8% 0.052 248.5)
-
Step 400
400
#77A5D3
oklch(70.7% 0.084 249.1)
-
Step 500
500
#538EC7
oklch(63.1% 0.106 249.1)
-
Step 600
600 (this color)
#3173AF
oklch(54.2% 0.115 249)
-
Step 700
700
#27649B
oklch(49.1% 0.108 249)
-
Step 800
800
#22527D
oklch(42.7% 0.088 248.5)
-
Step 900
900
#214465
oklch(37.7% 0.07 248.9)
-
Step 950
950
#14283B
oklch(27% 0.044 248.6)
#3173AF 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) | #5876B2 | 0.041 |
| Deuteranopia (no green cones) | #466AAE | 0.029 |
| Tritanopia (no blue cones) | #008189 | 0.085 |
| Achromatopsia (no color) | #6F6F6F | 0.115 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3173AF
#3173AF
oklch(54.2% 0.115 249)
- #9A6108
#9A6108
oklch(54.3% 0.116 69.2)
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 #3173AF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.014
- Nice Blue #107AB0 ΔE 0.023
- French Blue #436BAD ΔE 0.025
- Muted Blue #3B719F ΔE 0.025
- Windows Blue #3778BF ΔE 0.028
- Mid Blue #276AB3 ΔE 0.030
- Dull Blue #49759C ΔE 0.038
- Ocean Blue #03719C ΔE 0.039
Use #3173AF 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.