#173A5E
Closest named color: Prussian Blue (#1D3557). oklch(34.2% 0.075 251.5), rgb(23, 58, 94).
Aa
White text reads best on this color (11.64:1).
About this color
#173A5E is a dark, moderately saturated blue. In OKLCH its lightness is 34%, its chroma 0.075 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.018 away. White text reads best on it, at 11.64:1.
| Hue family | Blues |
| Lightness | dark (34%) |
| Chroma | moderately saturated (0.075) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.80:1 |
| White text | 11.64:1 |
Values
| HEX | #173A5E |
| RGB | rgb(23, 58, 94) |
| HSL | hsl(210, 61%, 23%) |
| OKLCH | oklch(34.2% 0.075 251.5) |
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 #173A5E | 11.64:1 | AAA | Lc -100.2 | Preferred for body text |
| Black text on #173A5E | 1.80:1 | Fails | Lc 7.3 | Not readable |
| #173A5E text on white | 11.64:1 | AAA | Lc 96.5 | Preferred for body text |
| #173A5E text on black | 1.80:1 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF5
oklch(93.6% 0.017 250.8)
-
Step 200
200
#CBDBEE
oklch(88.5% 0.031 252.7)
-
Step 300
300
#A7C4E5
oklch(81% 0.056 251.8)
-
Step 400
400
#76A4D7
oklch(70.6% 0.09 251.7)
-
Step 500
500
#518DCD
oklch(63.1% 0.116 251.5)
-
Step 600
600
#3476BA
oklch(55.6% 0.125 251.7)
-
Step 700
700
#2663A0
oklch(49.1% 0.116 251.4)
-
Step 800
800
#215182
oklch(42.7% 0.097 251.5)
-
Step 900
900 (this color)
#173A5E
oklch(34.2% 0.075 251.5)
-
Step 950
950
#14283D
oklch(27.1% 0.047 251)
#173A5E 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) | #2A3C5F | 0.023 |
| Deuteranopia (no green cones) | #1F355D | 0.016 |
| Tritanopia (no blue cones) | #004247 | 0.057 |
| Achromatopsia (no color) | #383838 | 0.075 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173A5E
#173A5E
oklch(34.2% 0.075 251.5)
- #503100
#503100
oklch(34.3% 0.074 71.3)
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 #173A5E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.018
- Marine Blue #01386A ΔE 0.027
- Dark Blue Grey #1F3B4D ΔE 0.032
- Midnight Green #073B4C ΔE 0.036
- Marine #042E60 ΔE 0.043
- Dark Grey Blue #29465B ΔE 0.047
- Twilight Blue #0A437A ΔE 0.051
- Charcoal #264653 ΔE 0.052
Use #173A5E 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.