#173A7C
Closest named color: Twilight Blue (#0A437A). oklch(36.4% 0.12 261.6), rgb(23, 58, 124).
Aa
White text reads best on this color (10.86:1).
About this color
#173A7C is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.120 and its hue 262°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.026 away. White text reads best on it, at 10.86:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.120) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.93:1 |
| White text | 10.86:1 |
Values
| HEX | #173A7C |
| RGB | rgb(23, 58, 124) |
| HSL | hsl(219, 69%, 29%) |
| OKLCH | oklch(36.4% 0.12 261.6) |
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 #173A7C | 10.86:1 | AAA | Lc -98.7 | Preferred for body text |
| Black text on #173A7C | 1.93:1 | Fails | Lc 9.2 | Not readable |
| #173A7C text on white | 10.86:1 | AAA | Lc 94.7 | Preferred for body text |
| #173A7C text on black | 1.93:1 | Fails | Lc -7.9 | 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
#F1F6FE
oklch(97.2% 0.012 259.8)
-
Step 100
100
#E0EAFC
oklch(93.5% 0.027 262.3)
-
Step 200
200
#C7DAFB
oklch(88.5% 0.05 261.5)
-
Step 300
300
#A1C1FB
oklch(80.8% 0.09 262.1)
-
Step 400
400
#6D9FF9
oklch(70.7% 0.143 261.4)
-
Step 500
500
#4684F6
oklch(63.1% 0.183 261.3)
-
Step 600
600
#286AE5
oklch(55.6% 0.199 261.4)
-
Step 700
700
#1C57C7
oklch(49% 0.185 261.7)
-
Step 800
800
#1948A1
oklch(42.7% 0.153 261.6)
-
Step 900
900 (this color)
#173A7C
oklch(36.4% 0.12 261.6)
-
Step 950
950
#10254B
oklch(27.1% 0.076 261.2)
#173A7C 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) | #0E427E | 0.022 |
| Deuteranopia (no green cones) | #00397B | 0.015 |
| Tritanopia (no blue cones) | #004A55 | 0.093 |
| Achromatopsia (no color) | #3D3D3D | 0.120 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173A7C
#173A7C
oklch(36.4% 0.12 261.6)
- #523900
#523900
oklch(36.4% 0.075 81)
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 #173A7C, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.026
- Marine Blue #01386A ΔE 0.036
- Cobalt #1E488F ΔE 0.050
- Marine #042E60 ΔE 0.062
- Prussian Blue #1D3557 ΔE 0.064
- Light Navy #155084 ΔE 0.064
- Dark Slate Blue #483D8B ΔE 0.072
- Deep Sea Blue #015482 ΔE 0.075
Use #173A7C 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.