#517DB5
Closest named color: Steel Blue (#4682B4). oklch(58.2% 0.1 255), rgb(81, 125, 181).
Aa
Black text reads best on this color (4.95:1).
About this color
#517DB5 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 58%, its chroma 0.100 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Steel Blue (#4682B4), ΔE 0.017 away. Black text reads best on it, at 4.95:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | moderately saturated (0.100) |
| Temperature | cool |
| Nearest name | Steel Blue (#4682B4) |
| Black text | 4.95:1 |
| White text | 4.24:1 |
Values
| HEX | #517DB5 |
| RGB | rgb(81, 125, 181) |
| HSL | hsl(214, 40%, 51%) |
| OKLCH | oklch(58.2% 0.1 255) |
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 #517DB5 | 4.24:1 | AA large text | Lc -74.7 | Content text, not long reading |
| Black text on #517DB5 | 4.95:1 | AA | Lc 34.9 | Non-text elements, placeholder text |
| #517DB5 text on white | 4.24:1 | AA large text | Lc 69.2 | Content text, not long reading |
| #517DB5 text on black | 4.95:1 | AA | Lc -32.5 | 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 600.
-
Step 50
50
#F3F6F9
oklch(97.2% 0.005 247.9)
-
Step 100
100
#E4EAF3
oklch(93.5% 0.014 258.3)
-
Step 200
200
#CEDAEA
oklch(88.4% 0.026 255.6)
-
Step 300
300
#AEC3DE
oklch(81% 0.045 254.8)
-
Step 400
400
#83A3CD
oklch(70.7% 0.071 255.4)
-
Step 500
500
#638CC0
oklch(63.1% 0.091 254.8)
-
Step 600
600 (this color)
#517DB5
oklch(58.2% 0.1 255)
-
Step 700
700
#3B6294
oklch(49.1% 0.092 255.3)
-
Step 800
800
#315078
oklch(42.6% 0.076 255.4)
-
Step 900
900
#2B4361
oklch(37.8% 0.06 254.6)
-
Step 950
950
#1A2739
oklch(27% 0.038 256.7)
#517DB5 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) | #6680B7 | 0.027 |
| Deuteranopia (no green cones) | #5A77B4 | 0.018 |
| Tritanopia (no blue cones) | #0F8A91 | 0.088 |
| Achromatopsia (no color) | #7B7B7B | 0.100 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #517DB5
#517DB5
oklch(58.2% 0.1 255)
- #9D722F
#9D722F
oklch(58.3% 0.099 75.4)
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 #517DB5, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Steel Blue #4682B4 ΔE 0.017
- Cool Blue #4984B8 ΔE 0.020
- Off Blue #5684AE ΔE 0.026
- Dusty Blue #5A86AD ΔE 0.034
- Windows Blue #3778BF ΔE 0.034
- Stormy Blue #507B9C ΔE 0.039
- Cerulean #457B9D ΔE 0.041
- Flat Blue #3C73A8 ΔE 0.041
Use #517DB5 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.