#173F76
Closest named color: Twilight Blue (#0A437A). oklch(37.2% 0.104 257.3), rgb(23, 63, 118).
Aa
White text reads best on this color (10.45:1).
About this color
#173F76 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.104 and its hue 257°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.013 away. White text reads best on it, at 10.45:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.104) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 2.00:1 |
| White text | 10.45:1 |
Values
| HEX | #173F76 |
| RGB | rgb(23, 63, 118) |
| HSL | hsl(215, 67%, 28%) |
| OKLCH | oklch(37.2% 0.104 257.3) |
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 #173F76 | 10.45:1 | AAA | Lc -97.9 | Preferred for body text |
| Black text on #173F76 | 2.00:1 | Fails | Lc 10.0 | Not readable |
| #173F76 text on white | 10.45:1 | AAA | Lc 93.9 | Preferred for body text |
| #173F76 text on black | 2.00:1 | Fails | Lc -8.6 | 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
#E1EBF9
oklch(93.7% 0.022 256.7)
-
Step 200
200
#C7DBF6
oklch(88.5% 0.043 255.9)
-
Step 300
300
#A1C3F3
oklch(80.9% 0.078 257)
-
Step 400
400
#6DA2EE
oklch(70.7% 0.126 257.4)
-
Step 500
500
#4488E8
oklch(63% 0.16 257.5)
-
Step 600
600
#2370D6
oklch(55.6% 0.173 257.3)
-
Step 700
700
#145DBA
oklch(49.1% 0.162 257.3)
-
Step 800
800
#154C96
oklch(42.6% 0.134 257.6)
-
Step 900
900 (this color)
#173F76
oklch(37.2% 0.104 257.3)
-
Step 950
950
#102646
oklch(27% 0.066 257.9)
#173F76 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) | #234478 | 0.020 |
| Deuteranopia (no green cones) | #0F3B75 | 0.014 |
| Tritanopia (no blue cones) | #004C54 | 0.081 |
| Achromatopsia (no color) | #3F3F3F | 0.104 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173F76
#173F76
oklch(37.2% 0.104 257.3)
- #573A00
#573A00
oklch(37.3% 0.078 77.3)
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 #173F76, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.013
- Marine Blue #01386A ΔE 0.034
- Cobalt #1E488F ΔE 0.048
- Light Navy #155084 ΔE 0.053
- Prussian Blue #1D3557 ΔE 0.057
- Dark Grey Blue #29465B ΔE 0.059
- Deep Sea Blue #015482 ΔE 0.062
- Marine #042E60 ΔE 0.065
Use #173F76 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.