#173E9F
Closest named color: Sapphire (#2138AB). oklch(40.3% 0.164 263.8), rgb(23, 62, 159).
Aa
White text reads best on this color (9.43:1).
About this color
#173E9F is a dark, vivid blue. In OKLCH its lightness is 40%, its chroma 0.164 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Sapphire (#2138AB), ΔE 0.024 away. White text reads best on it, at 9.43:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | vivid (0.164) |
| Temperature | cool |
| Nearest name | Sapphire (#2138AB) |
| Black text | 2.22:1 |
| White text | 9.43:1 |
Values
| HEX | #173E9F |
| RGB | rgb(23, 62, 159) |
| HSL | hsl(223, 75%, 36%) |
| OKLCH | oklch(40.3% 0.164 263.8) |
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 #173E9F | 9.43:1 | AAA | Lc -95.5 | Preferred for body text |
| Black text on #173E9F | 2.22:1 | Fails | Lc 12.8 | Not readable |
| #173E9F text on white | 9.43:1 | AAA | Lc 91.1 | Preferred for body text |
| #173E9F text on black | 2.22:1 | Fails | Lc -11.2 | 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 800.
-
Step 50
50
#F1F6FE
oklch(97.2% 0.012 259.8)
-
Step 100
100
#E0EAFD
oklch(93.5% 0.028 263.4)
-
Step 200
200
#C7DAFD
oklch(88.5% 0.053 262.7)
-
Step 300
300
#A1C0FF
oklch(80.8% 0.096 264.1)
-
Step 400
400
#6F9DFF
oklch(70.7% 0.152 263.9)
-
Step 500
500
#4A81FE
oklch(63.2% 0.195 263.8)
-
Step 600
600
#2E66ED
oklch(55.6% 0.212 263.8)
-
Step 700
700
#2253CE
oklch(49% 0.198 263.9)
-
Step 800
800 (this color)
#173E9F
oklch(40.3% 0.164 263.8)
-
Step 900
900
#1D3C84
oklch(37.8% 0.127 263.8)
-
Step 950
950
#11244D
oklch(27.1% 0.08 263.3)
#173E9F 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) | #004DA2 | 0.038 |
| Deuteranopia (no green cones) | #00409D | 0.012 |
| Tritanopia (no blue cones) | #005768 | 0.126 |
| Achromatopsia (no color) | #464646 | 0.164 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173E9F
#173E9F
oklch(40.3% 0.164 263.8)
- #5E4400
#5E4400
oklch(40.4% 0.083 83.7)
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 #173E9F, closest first.
No curated palette has a color within ΔE 0.04 of #173E9F.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Sapphire #2138AB ΔE 0.024
- Cobalt #1E488F ΔE 0.039
- Blueberry #464196 ΔE 0.060
- Twilight Blue #0A437A ΔE 0.065
- Blue Blue #2242C7 ΔE 0.067
- Dark Slate Blue #483D8B ΔE 0.068
- Dusk Blue #26538D ΔE 0.070
- Light Navy #155084 ΔE 0.070
Use #173E9F 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.