#3173BB
Closest named color: Windows Blue (#3778BF). oklch(54.9% 0.131 253), rgb(49, 115, 187).
Aa
White text reads best on this color (4.88:1).
About this color
#3173BB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.131 and its hue 253°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.016 away. White text reads best on it, at 4.88:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.131) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.30:1 |
| White text | 4.88:1 |
Values
| HEX | #3173BB |
| RGB | rgb(49, 115, 187) |
| HSL | hsl(211, 58%, 46%) |
| OKLCH | oklch(54.9% 0.131 253) |
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 #3173BB | 4.88:1 | AA | Lc -78.9 | Fine for body text |
| Black text on #3173BB | 4.30:1 | AA large text | Lc 30.6 | Non-text elements, placeholder text |
| #3173BB text on white | 4.88:1 | AA | Lc 73.5 | Content text, not long reading |
| #3173BB text on black | 4.30:1 | AA large text | Lc -28.2 | 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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF5
oklch(93.6% 0.017 250.8)
-
Step 200
200
#CADBEF
oklch(88.5% 0.033 252.5)
-
Step 300
300
#A6C4E6
oklch(81% 0.058 251.8)
-
Step 400
400
#76A4DA
oklch(70.7% 0.094 253)
-
Step 500
500
#518CD0
oklch(63% 0.12 253.2)
-
Step 600
600 (this color)
#3173BB
oklch(54.9% 0.131 253)
-
Step 700
700
#2562A3
oklch(49.1% 0.121 252.8)
-
Step 800
800
#215084
oklch(42.6% 0.101 253.2)
-
Step 900
900
#20436A
oklch(37.7% 0.079 252.8)
-
Step 950
950
#14273E
oklch(26.9% 0.05 254.1)
#3173BB 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) | #5278BE | 0.036 |
| Deuteranopia (no green cones) | #3C6BBA | 0.022 |
| Tritanopia (no blue cones) | #00848E | 0.099 |
| Achromatopsia (no color) | #717171 | 0.131 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3173BB
#3173BB
oklch(54.9% 0.131 253)
- #9A6400
#9A6400
oklch(54.8% 0.117 72.5)
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 #3173BB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.016
- Mid Blue #276AB3 ΔE 0.029
- French Blue #436BAD ΔE 0.029
- Flat Blue #3C73A8 ΔE 0.031
- Nice Blue #107AB0 ΔE 0.032
- Muted Blue #3B719F ΔE 0.044
- Steel Blue #4682B4 ΔE 0.052
- Dull Blue #49759C ΔE 0.054
Use #3173BB 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.