#173771
Closest named color: Marine Blue (#01386A). oklch(34.9% 0.107 261.1), rgb(23, 55, 113).
Aa
White text reads best on this color (11.52:1).
About this color
#173771 is a dark, moderately saturated blue. In OKLCH its lightness is 35%, its chroma 0.107 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is Marine Blue (#01386A), ΔE 0.019 away. White text reads best on it, at 11.52:1.
| Hue family | Blues |
| Lightness | dark (35%) |
| Chroma | moderately saturated (0.107) |
| Temperature | cool |
| Nearest name | Marine Blue (#01386A) |
| Black text | 1.82:1 |
| White text | 11.52:1 |
Values
| HEX | #173771 |
| RGB | rgb(23, 55, 113) |
| HSL | hsl(219, 66%, 27%) |
| OKLCH | oklch(34.9% 0.107 261.1) |
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 #173771 | 11.52:1 | AAA | Lc -99.9 | Preferred for body text |
| Black text on #173771 | 1.82:1 | Fails | Lc 7.7 | Not readable |
| #173771 text on white | 11.52:1 | AAA | Lc 96.2 | Preferred for body text |
| #173771 text on black | 1.82:1 | Fails | Lc 0.0 | 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
#E1EAFA
oklch(93.5% 0.024 262.1)
-
Step 200
200
#C9DAF7
oklch(88.5% 0.044 261.2)
-
Step 300
300
#A4C2F5
oklch(81% 0.08 260.9)
-
Step 400
400
#72A0F1
oklch(70.7% 0.129 261.1)
-
Step 500
500
#4D86EC
oklch(63.2% 0.165 261.1)
-
Step 600
600
#316DDA
oklch(55.7% 0.179 261.1)
-
Step 700
700
#245ABD
oklch(49.1% 0.166 261.3)
-
Step 800
800
#1F4A99
oklch(42.7% 0.138 261.3)
-
Step 900
900 (this color)
#173771
oklch(34.9% 0.107 261.1)
-
Step 950
950
#122547
oklch(26.9% 0.068 261.1)
#173771 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) | #153D73 | 0.017 |
| Deuteranopia (no green cones) | #003570 | 0.017 |
| Tritanopia (no blue cones) | #00454E | 0.085 |
| Achromatopsia (no color) | #393939 | 0.107 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173771
#173771
oklch(34.9% 0.107 261.1)
- #4D3500
#4D3500
oklch(34.8% 0.072 80.6)
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 #173771, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Marine Blue #01386A ΔE 0.019
- Twilight Blue #0A437A ΔE 0.036
- Marine #042E60 ΔE 0.043
- Prussian Blue #1D3557 ΔE 0.045
- Dark Blue Grey #1F3B4D ΔE 0.068
- Cobalt #1E488F ΔE 0.068
- Dark Grey Blue #29465B ΔE 0.070
- Midnight Green #073B4C ΔE 0.071
Use #173771 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.