#3173D1
Closest named color: Windows Blue (#3778BF). oklch(56.3% 0.16 257.9), rgb(49, 115, 209).
Aa
White text reads best on this color (4.66:1).
About this color
#3173D1 is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.160 and its hue 258°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.034 away. White text reads best on it, at 4.66:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.160) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.50:1 |
| White text | 4.66:1 |
Values
| HEX | #3173D1 |
| RGB | rgb(49, 115, 209) |
| HSL | hsl(215, 63%, 51%) |
| OKLCH | oklch(56.3% 0.16 257.9) |
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 #3173D1 | 4.66:1 | AA | Lc -77.4 | Fine for body text |
| Black text on #3173D1 | 4.50:1 | AA | Lc 32.1 | Non-text elements, placeholder text |
| #3173D1 text on white | 4.66:1 | AA | Lc 72.0 | Content text, not long reading |
| #3173D1 text on black | 4.50:1 | AA | Lc -29.7 | 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
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#E1EBF8
oklch(93.6% 0.021 254.9)
-
Step 200
200
#C9DBF4
oklch(88.6% 0.04 256.6)
-
Step 300
300
#A4C3EF
oklch(81% 0.071 257.1)
-
Step 400
400
#72A2E8
oklch(70.7% 0.116 257.7)
-
Step 500
500
#4D89E1
oklch(63.1% 0.147 258)
-
Step 600
600 (this color)
#3173D1
oklch(56.3% 0.16 257.9)
-
Step 700
700
#215EB3
oklch(49.1% 0.149 257.8)
-
Step 800
800
#1E4D91
oklch(42.7% 0.123 258.1)
-
Step 900
900
#1E4173
oklch(37.7% 0.095 257.6)
-
Step 950
950
#122644
oklch(26.9% 0.062 258.3)
#3173D1 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) | #427CD5 | 0.030 |
| Deuteranopia (no green cones) | #1F6DCF | 0.022 |
| Tritanopia (no blue cones) | #008998 | 0.122 |
| Achromatopsia (no color) | #747474 | 0.160 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3173D1
#3173D1
oklch(56.3% 0.16 257.9)
- #9B6B00
#9B6B00
oklch(56.3% 0.118 77.7)
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 #3173D1, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.034
- Royal Blue #4169E1 ΔE 0.039
- Cerulean Blue #056EEE ΔE 0.051
- Mid Blue #276AB3 ΔE 0.052
- Water Blue #0E87CC ΔE 0.056
- French Blue #436BAD ΔE 0.057
- Nice Blue #107AB0 ΔE 0.061
- Flat Blue #3C73A8 ΔE 0.064
Use #3173D1 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.