#173C79
Closest named color: Twilight Blue (#0A437A). oklch(36.7% 0.113 259.9), rgb(23, 60, 121).
Aa
White text reads best on this color (10.72:1).
About this color
#173C79 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.113 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.020 away. White text reads best on it, at 10.72:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.113) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.95:1 |
| White text | 10.72:1 |
Values
| HEX | #173C79 |
| RGB | rgb(23, 60, 121) |
| HSL | hsl(217, 68%, 28%) |
| OKLCH | oklch(36.7% 0.113 259.9) |
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 #173C79 | 10.72:1 | AAA | Lc -98.4 | Preferred for body text |
| Black text on #173C79 | 1.95:1 | Fails | Lc 9.5 | Not readable |
| #173C79 text on white | 10.72:1 | AAA | Lc 94.5 | Preferred for body text |
| #173C79 text on black | 1.95:1 | Fails | Lc -8.1 | Not readable |
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 900.
-
Step 50
50
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E1EBFB
oklch(93.7% 0.024 259.8)
-
Step 200
200
#C7DAF9
oklch(88.4% 0.048 260.2)
-
Step 300
300
#A1C2F8
oklch(80.9% 0.085 260.1)
-
Step 400
400
#6DA0F4
oklch(70.6% 0.135 260)
-
Step 500
500
#4686F0
oklch(63.1% 0.172 259.9)
-
Step 600
600
#276DDF
oklch(55.7% 0.188 260)
-
Step 700
700
#195AC1
oklch(49.1% 0.174 259.9)
-
Step 800
800
#184A9C
oklch(42.7% 0.144 260)
-
Step 900
900 (this color)
#173C79
oklch(36.7% 0.113 259.9)
-
Step 950
950
#102549
oklch(26.9% 0.072 260.4)
#173C79 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) | #19437B | 0.021 |
| Deuteranopia (no green cones) | #003A78 | 0.016 |
| Tritanopia (no blue cones) | #004B54 | 0.089 |
| Achromatopsia (no color) | #3E3E3E | 0.113 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173C79
#173C79
oklch(36.7% 0.113 259.9)
- #543900
#543900
oklch(36.6% 0.076 78.9)
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 #173C79, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.020
- Marine Blue #01386A ΔE 0.033
- Cobalt #1E488F ΔE 0.049
- Prussian Blue #1D3557 ΔE 0.060
- Light Navy #155084 ΔE 0.060
- Marine #042E60 ΔE 0.062
- Dark Grey Blue #29465B ΔE 0.068
- Deep Sea Blue #015482 ΔE 0.070
Use #173C79 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.