#173789
Closest named color: Twilight Blue (#0A437A). oklch(36.9% 0.142 264.3), rgb(23, 55, 137).
Aa
White text reads best on this color (10.80:1).
About this color
#173789 is a dark, vivid blue. In OKLCH its lightness is 37%, its chroma 0.142 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.044 away. White text reads best on it, at 10.80:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | vivid (0.142) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.94:1 |
| White text | 10.80:1 |
Values
| HEX | #173789 |
| RGB | rgb(23, 55, 137) |
| HSL | hsl(223, 71%, 31%) |
| OKLCH | oklch(36.9% 0.142 264.3) |
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 #173789 | 10.80:1 | AAA | Lc -98.4 | Preferred for body text |
| Black text on #173789 | 1.94:1 | Fails | Lc 9.5 | Not readable |
| #173789 text on white | 10.80:1 | AAA | Lc 94.5 | Preferred for body text |
| #173789 text on black | 1.94:1 | 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
#F1F6FF
oklch(97.2% 0.013 262.4)
-
Step 100
100
#E0EAFF
oklch(93.6% 0.03 265.3)
-
Step 200
200
#C7D9FF
oklch(88.4% 0.056 265.2)
-
Step 300
300
#A2C0FF
oklch(80.9% 0.096 264.7)
-
Step 400
400
#709DFF
oklch(70.7% 0.152 264.2)
-
Step 500
500
#4A80FF
oklch(63.1% 0.198 264.2)
-
Step 600
600
#2861FB
oklch(55.7% 0.237 264.3)
-
Step 700
700
#1C4EDB
oklch(49.1% 0.221 264.3)
-
Step 800
800
#1841B1
oklch(42.6% 0.184 264.3)
-
Step 900
900 (this color)
#173789
oklch(36.9% 0.142 264.3)
-
Step 950
950
#0F2352
oklch(27.1% 0.09 264)
#173789 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) | #00438C | 0.032 |
| Deuteranopia (no green cones) | #003887 | 0.014 |
| Tritanopia (no blue cones) | #004C5A | 0.111 |
| Achromatopsia (no color) | #3D3D3D | 0.142 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173789
#173789
oklch(36.9% 0.142 264.3)
- #523B00
#523B00
oklch(36.8% 0.076 83.9)
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 #173789, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.044
- Cobalt #1E488F ΔE 0.048
- Marine Blue #01386A ΔE 0.056
- Sapphire #2138AB ΔE 0.058
- Royal #0C1793 ΔE 0.069
- Dark Slate Blue #483D8B ΔE 0.070
- Light Navy #155084 ΔE 0.072
- Blueberry #464196 ΔE 0.073
Use #173789 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.