#173C91
Closest named color: Cobalt (#1E488F). oklch(38.7% 0.147 263.4), rgb(23, 60, 145).
Aa
White text reads best on this color (10.03:1).
About this color
#173C91 is a dark, vivid blue. In OKLCH its lightness is 39%, its chroma 0.147 and its hue 263°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.035 away. White text reads best on it, at 10.03:1.
| Hue family | Blues |
| Lightness | dark (39%) |
| Chroma | vivid (0.147) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.09:1 |
| White text | 10.03:1 |
Values
| HEX | #173C91 |
| RGB | rgb(23, 60, 145) |
| HSL | hsl(222, 73%, 33%) |
| OKLCH | oklch(38.7% 0.147 263.4) |
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 #173C91 | 10.03:1 | AAA | Lc -96.9 | Preferred for body text |
| Black text on #173C91 | 2.09:1 | Fails | Lc 11.2 | Not readable |
| #173C91 text on white | 10.03:1 | AAA | Lc 92.7 | Preferred for body text |
| #173C91 text on black | 2.09:1 | Fails | Lc -9.7 | 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
#DFEAFF
oklch(93.5% 0.031 263.5)
-
Step 200
200
#C6DAFF
oklch(88.5% 0.056 262.8)
-
Step 300
300
#A1C1FF
oklch(81% 0.095 263.3)
-
Step 400
400
#6E9DFF
oklch(70.6% 0.153 263.6)
-
Step 500
500
#4781FF
oklch(63.2% 0.197 263.3)
-
Step 600
600
#1E60FF
oklch(55.6% 0.245 263.4)
-
Step 700
700
#114DDF
oklch(49.1% 0.229 263.4)
-
Step 800
800
#1141B4
oklch(42.7% 0.189 263.4)
-
Step 900
900 (this color)
#173C91
oklch(38.7% 0.147 263.4)
-
Step 950
950
#0D2253
oklch(26.9% 0.094 263.8)
#173C91 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) | #004894 | 0.031 |
| Deuteranopia (no green cones) | #003D8F | 0.012 |
| Tritanopia (no blue cones) | #005160 | 0.113 |
| Achromatopsia (no color) | #424242 | 0.147 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173C91
#173C91
oklch(38.7% 0.147 263.4)
- #583F00
#583F00
oklch(38.5% 0.079 83.1)
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 #173C91, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.035
- Sapphire #2138AB ΔE 0.044
- Twilight Blue #0A437A ΔE 0.045
- Blueberry #464196 ΔE 0.062
- Light Navy #155084 ΔE 0.063
- Dark Slate Blue #483D8B ΔE 0.064
- Dusk Blue #26538D ΔE 0.069
- Marine Blue #01386A ΔE 0.070
Use #173C91 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.