#173B4F
Closest named color: Dark Blue Grey (#1F3B4D). oklch(33.6% 0.054 235.9), rgb(23, 59, 79).
Aa
White text reads best on this color (11.83:1).
About this color
#173B4F is a dark, muted blue. In OKLCH its lightness is 34%, its chroma 0.054 and its hue 236°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.008 away. White text reads best on it, at 11.83:1.
| Hue family | Blues |
| Lightness | dark (34%) |
| Chroma | muted (0.054) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.77:1 |
| White text | 11.83:1 |
Values
| HEX | #173B4F |
| RGB | rgb(23, 59, 79) |
| HSL | hsl(201, 55%, 20%) |
| OKLCH | oklch(33.6% 0.054 235.9) |
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 #173B4F | 11.83:1 | AAA | Lc -100.6 | Preferred for body text |
| Black text on #173B4F | 1.77:1 | Fails | Lc 0.0 | Not readable |
| #173B4F text on white | 11.83:1 | AAA | Lc 97.0 | Preferred for body text |
| #173B4F text on black | 1.77:1 | 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
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E3EBF1
oklch(93.6% 0.012 239.9)
-
Step 200
200
#CCDCE6
oklch(88.5% 0.022 235)
-
Step 300
300
#A8C5D8
oklch(80.8% 0.041 236.8)
-
Step 400
400
#79A7C4
oklch(70.6% 0.065 236.6)
-
Step 500
500
#5591B5
oklch(63% 0.083 236.5)
-
Step 600
600
#377BA1
oklch(55.6% 0.09 236.1)
-
Step 700
700
#29688A
oklch(49.2% 0.084 235.8)
-
Step 800
800
#235570
oklch(42.8% 0.07 235.3)
-
Step 900
900 (this color)
#173B4F
oklch(33.6% 0.054 235.9)
-
Step 950
950
#152935
oklch(27% 0.034 236.3)
#173B4F 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) | #323B50 | 0.034 |
| Deuteranopia (no green cones) | #2A354F | 0.028 |
| Tritanopia (no blue cones) | #004042 | 0.036 |
| Achromatopsia (no color) | #373737 | 0.054 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173B4F
#173B4F
oklch(33.6% 0.054 235.9)
- #4C2F1A
#4C2F1A
oklch(33.6% 0.054 55.6)
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 #173B4F, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.008
- Midnight Green #073B4C ΔE 0.013
- Prussian Blue #1D3557 ΔE 0.028
- Gunmetal #293241 ΔE 0.036
- Charcoal #264653 ΔE 0.042
- Onyx #343A40 ΔE 0.042
- Dark Grey Blue #29465B ΔE 0.045
- Space Cadet #2B2D42 ΔE 0.049
Use #173B4F 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.