#173F4F
Closest named color: Dark Blue Grey (#1F3B4D). oklch(34.7% 0.052 227.6), rgb(23, 63, 79).
Aa
White text reads best on this color (11.28:1).
About this color
#173F4F is a dark, muted teal or cyan. In OKLCH its lightness is 35%, its chroma 0.052 and its hue 228°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Blue Grey (#1F3B4D), ΔE 0.014 away. White text reads best on it, at 11.28:1.
| Hue family | Teals and cyans |
| Lightness | dark (35%) |
| Chroma | muted (0.052) |
| Temperature | cool |
| Nearest name | Dark Blue Grey (#1F3B4D) |
| Black text | 1.86:1 |
| White text | 11.28:1 |
Values
| HEX | #173F4F |
| RGB | rgb(23, 63, 79) |
| HSL | hsl(197, 55%, 20%) |
| OKLCH | oklch(34.7% 0.052 227.6) |
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 #173F4F | 11.28:1 | AAA | Lc -99.6 | Preferred for body text |
| Black text on #173F4F | 1.86:1 | Fails | Lc 8.0 | Not readable |
| #173F4F text on white | 11.28:1 | AAA | Lc 95.9 | Preferred for body text |
| #173F4F text on black | 1.86:1 | 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
#F2F6F8
oklch(97.1% 0.005 228.8)
-
Step 100
100
#E2ECF0
oklch(93.7% 0.012 223.5)
-
Step 200
200
#CBDCE5
oklch(88.4% 0.022 230.6)
-
Step 300
300
#A7C6D5
oklch(80.9% 0.04 228.7)
-
Step 400
400
#76A9BF
oklch(70.7% 0.063 226.7)
-
Step 500
500
#5093B0
oklch(63.1% 0.081 228.2)
-
Step 600
600
#317D9B
oklch(55.6% 0.087 227.7)
-
Step 700
700
#226985
oklch(49% 0.082 228.5)
-
Step 800
800
#1F566C
oklch(42.7% 0.067 228.1)
-
Step 900
900 (this color)
#173F4F
oklch(34.7% 0.052 227.6)
-
Step 950
950
#142A33
oklch(27.1% 0.033 226.5)
#173F4F 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) | #373E50 | 0.039 |
| Deuteranopia (no green cones) | #2F384F | 0.034 |
| Tritanopia (no blue cones) | #004444 | 0.033 |
| Achromatopsia (no color) | #3A3A3A | 0.052 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173F4F
#173F4F
oklch(34.7% 0.052 227.6)
- #503121
#503121
oklch(34.7% 0.052 47.8)
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 #173F4F, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Blue Grey #1F3B4D ΔE 0.014
- Midnight Green #073B4C ΔE 0.019
- Charcoal #264653 ΔE 0.030
- Dark Grey Blue #29465B ΔE 0.036
- Prussian Blue #1D3557 ΔE 0.039
- Onyx #343A40 ΔE 0.040
- Gunmetal #293241 ΔE 0.045
- Dark Teal #014D4E ΔE 0.048
Use #173F4F 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.