#3F666D
Closest named color: Slate (#516572). oklch(48.4% 0.045 210.1), rgb(63, 102, 109).
Aa
White text reads best on this color (6.30:1).
About this color
#3F666D is a medium-dark, muted teal or cyan. In OKLCH its lightness is 48%, its chroma 0.045 and its hue 210°. Its hue sits on the cool side of the wheel. The nearest named color is Slate (#516572), ΔE 0.025 away. White text reads best on it, at 6.30:1.
| Hue family | Teals and cyans |
| Lightness | medium-dark (48%) |
| Chroma | muted (0.045) |
| Temperature | cool |
| Nearest name | Slate (#516572) |
| Black text | 3.33:1 |
| White text | 6.30:1 |
Values
| HEX | #3F666D |
| RGB | rgb(63, 102, 109) |
| HSL | hsl(189, 27%, 34%) |
| OKLCH | oklch(48.4% 0.045 210.1) |
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 #3F666D | 6.30:1 | AA | Lc -86.4 | Fine for body text |
| Black text on #3F666D | 3.33:1 | AA large text | Lc 22.8 | Dividers and decoration only |
| #3F666D text on white | 6.30:1 | AA | Lc 81.3 | Fine for body text |
| #3F666D text on black | 3.33:1 | AA large text | Lc -20.6 | Dividers and decoration only |
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 700.
-
Step 50
50
#F3F6F6
oklch(97.1% 0.003 197.1)
-
Step 100
100
#E5EBEC
oklch(93.6% 0.007 208.8)
-
Step 200
200
#D0DBDD
oklch(88.4% 0.012 209.8)
-
Step 300
300
#B1C5C8
oklch(80.9% 0.022 207.6)
-
Step 400
400
#88A7AD
oklch(70.7% 0.035 210.7)
-
Step 500
500
#6A9199
oklch(63.1% 0.045 211.7)
-
Step 600
600
#517B83
oklch(55.5% 0.048 210.8)
-
Step 700
700 (this color)
#3F666D
oklch(48.4% 0.045 210.1)
-
Step 800
800
#36555A
oklch(42.7% 0.037 208.6)
-
Step 900
900
#2F464A
oklch(37.7% 0.029 209.5)
-
Step 950
950
#1C292B
oklch(27% 0.018 207.9)
#3F666D 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) | #60636D | 0.044 |
| Deuteranopia (no green cones) | #585D6D | 0.040 |
| Tritanopia (no blue cones) | #2C6968 | 0.023 |
| Achromatopsia (no color) | #606060 | 0.046 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F666D
#3F666D
oklch(48.4% 0.045 210.1)
- #765550
#765550
oklch(48.3% 0.045 28.6)
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 #3F666D, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Slate #516572 ΔE 0.025
- Dark Aqua #05696B ΔE 0.038
- YInMn Blue #415A77 ΔE 0.045
- Deep Turquoise #017374 ΔE 0.047
- Dark Aquamarine #017371 ΔE 0.048
- Dark Green Blue #1F6357 ΔE 0.049
- Petrol #005F6A ΔE 0.051
- Denim #3B638C ΔE 0.054
Use #3F666D 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.