#173A55
Closest named color: Dark Blue Grey (#1F3B4D). oklch(33.7% 0.063 244.6), rgb(23, 58, 85).
Aa
White text reads best on this color (11.84:1).
About this color
#173A55 is a dark, muted blue. In OKLCH its lightness is 34%, its chroma 0.063 and its hue 245°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.017 away. White text reads best on it, at 11.84:1.
| Hue family | Blues |
| Lightness | dark (34%) |
| Chroma | muted (0.063) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.77:1 |
| White text | 11.84:1 |
Values
| HEX | #173A55 |
| RGB | rgb(23, 58, 85) |
| HSL | hsl(206, 57%, 21%) |
| OKLCH | oklch(33.7% 0.063 244.6) |
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 #173A55 | 11.84:1 | AAA | Lc -100.6 | Preferred for body text |
| Black text on #173A55 | 1.77:1 | Fails | Lc 0.0 | Not readable |
| #173A55 text on white | 11.84:1 | AAA | Lc 97.0 | Preferred for body text |
| #173A55 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
#E3EBF2
oklch(93.6% 0.013 244.3)
-
Step 200
200
#CBDBEA
oklch(88.4% 0.027 246.4)
-
Step 300
300
#A8C5DD
oklch(81% 0.046 243.3)
-
Step 400
400
#78A6CD
oklch(70.7% 0.076 244.7)
-
Step 500
500
#548FC0
oklch(63% 0.097 245.2)
-
Step 600
600
#3779AC
oklch(55.7% 0.104 244.7)
-
Step 700
700
#286694
oklch(49.2% 0.097 244.2)
-
Step 800
800
#235378
oklch(42.7% 0.081 244.7)
-
Step 900
900 (this color)
#173A55
oklch(33.7% 0.063 244.6)
-
Step 950
950
#152838
oklch(26.9% 0.039 245.4)
#173A55 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) | #2E3B56 | 0.028 |
| Deuteranopia (no green cones) | #253554 | 0.020 |
| Tritanopia (no blue cones) | #004143 | 0.048 |
| Achromatopsia (no color) | #373737 | 0.063 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173A55
#173A55
oklch(33.7% 0.063 244.6)
- #4D2F0F
#4D2F0F
oklch(33.5% 0.063 64.1)
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 #173A55, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.017
- Prussian Blue #1D3557 ΔE 0.018
- Midnight Green #073B4C ΔE 0.021
- Marine Blue #01386A ΔE 0.041
- Gunmetal #293241 ΔE 0.041
- Dark Grey Blue #29465B ΔE 0.046
- Charcoal #264653 ΔE 0.046
- Space Cadet #2B2D42 ΔE 0.050
Use #173A55 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.