#517BD8
Closest named color: Windows Blue (#3778BF). oklch(59.8% 0.149 264.1), rgb(81, 123, 216).
Aa
Black text reads best on this color (5.17:1).
About this color
#517BD8 is a medium-dark, vivid blue. In OKLCH its lightness is 60%, its chroma 0.149 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.048 away. Black text reads best on it, at 5.17:1.
| Hue family | Blues |
| Lightness | medium-dark (60%) |
| Chroma | vivid (0.149) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 5.17:1 |
| White text | 4.05:1 |
Values
| HEX | #517BD8 |
| RGB | rgb(81, 123, 216) |
| HSL | hsl(221, 63%, 58%) |
| OKLCH | oklch(59.8% 0.149 264.1) |
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 #517BD8 | 4.05:1 | AA large text | Lc -73.1 | Content text, not long reading |
| Black text on #517BD8 | 5.17:1 | AA | Lc 36.5 | Non-text elements, placeholder text |
| #517BD8 text on white | 4.05:1 | AA large text | Lc 67.6 | Content text, not long reading |
| #517BD8 text on black | 5.17:1 | AA | Lc -34.1 | Non-text elements, placeholder text |
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 500.
-
Step 50
50
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E3EAF9
oklch(93.6% 0.022 265.8)
-
Step 200
200
#CCDAF5
oklch(88.6% 0.04 263.7)
-
Step 300
300
#A9C1F1
oklch(81% 0.073 264)
-
Step 400
400
#7B9FEA
oklch(70.7% 0.118 264.1)
-
Step 500
500 (this color)
#517BD8
oklch(59.8% 0.149 264.1)
-
Step 600
600
#416DD1
oklch(55.6% 0.162 264)
-
Step 700
700
#335AB5
oklch(49% 0.151 264.1)
-
Step 800
800
#2B4A93
oklch(42.7% 0.126 264.4)
-
Step 900
900
#263F75
oklch(37.8% 0.097 263.7)
-
Step 950
950
#172544
oklch(27% 0.061 264.4)
#517BD8 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) | #5085DC | 0.026 |
| Deuteranopia (no green cones) | #3B78D6 | 0.024 |
| Tritanopia (no blue cones) | #00909F | 0.126 |
| Achromatopsia (no color) | #7E7E7E | 0.150 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #517BD8
#517BD8
oklch(59.8% 0.149 264.1)
- #A27800
#A27800
oklch(59.8% 0.123 84)
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 #517BD8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.048
- Soft Blue #6488EA ΔE 0.049
- Dark Sky Blue #448EE4 ΔE 0.050
- Water Blue #0E87CC ΔE 0.054
- Royal Blue #4169E1 ΔE 0.055
- Cornflower #6A79F7 ΔE 0.057
- Cool Blue #4984B8 ΔE 0.061
- Clear Blue #247AFD ΔE 0.064
Use #517BD8 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.