#517DCF
Closest named color: Windows Blue (#3778BF). oklch(59.7% 0.135 261.8), rgb(81, 125, 207).
Aa
Black text reads best on this color (5.18:1).
About this color
#517DCF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 60%, its chroma 0.135 and its hue 262°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.039 away. Black text reads best on it, at 5.18:1.
| Hue family | Blues |
| Lightness | medium-dark (60%) |
| Chroma | moderately saturated (0.135) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 5.18:1 |
| White text | 4.05:1 |
Values
| HEX | #517DCF |
| RGB | rgb(81, 125, 207) |
| HSL | hsl(219, 57%, 56%) |
| OKLCH | oklch(59.7% 0.135 261.8) |
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 #517DCF | 4.05:1 | AA large text | Lc -73.0 | Content text, not long reading |
| Black text on #517DCF | 5.18:1 | AA | Lc 36.6 | Non-text elements, placeholder text |
| #517DCF text on white | 4.05:1 | AA large text | Lc 67.5 | Content text, not long reading |
| #517DCF text on black | 5.18:1 | 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
#E3EAF7
oklch(93.6% 0.019 263)
-
Step 200
200
#CCDAF2
oklch(88.5% 0.036 261.3)
-
Step 300
300
#A9C1EC
oklch(80.8% 0.067 262)
-
Step 400
400
#7CA1E3
oklch(70.8% 0.106 261.6)
-
Step 500
500 (this color)
#517DCF
oklch(59.7% 0.135 261.8)
-
Step 600
600
#4170C8
oklch(55.7% 0.146 261.7)
-
Step 700
700
#335DAD
oklch(49.1% 0.136 261.9)
-
Step 800
800
#2B4C8C
oklch(42.7% 0.113 262.2)
-
Step 900
900
#274070
oklch(37.7% 0.088 262.2)
-
Step 950
950
#172641
oklch(27% 0.055 261.4)
#517DCF 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) | #5984D2 | 0.022 |
| Deuteranopia (no green cones) | #4879CD | 0.015 |
| Tritanopia (no blue cones) | #008F9C | 0.114 |
| Achromatopsia (no color) | #7E7E7E | 0.135 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #517DCF
#517DCF
oklch(59.7% 0.135 261.8)
- #A47600
#A47600
oklch(59.6% 0.123 81.3)
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 #517DCF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.039
- Cool Blue #4984B8 ΔE 0.045
- Water Blue #0E87CC ΔE 0.046
- Steel Blue #4682B4 ΔE 0.049
- Dark Sky Blue #448EE4 ΔE 0.050
- Soft Blue #6488EA ΔE 0.054
- Off Blue #5684AE ΔE 0.059
- Faded Blue #658CBB ΔE 0.063
Use #517DCF 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.