#40666B
Closest named color: Slate (#516572). oklch(48.4% 0.044 206.3), rgb(64, 102, 107).
Aa
White text reads best on this color (6.30:1).
About this color
#40666B is a medium-dark, muted teal or cyan. In OKLCH its lightness is 48%, its chroma 0.044 and its hue 206°. Its hue sits on the cool side of the wheel. The nearest named color is Slate (#516572), ΔE 0.026 away. White text reads best on it, at 6.30:1.
| Hue family | Teals and cyans |
| Lightness | medium-dark (48%) |
| Chroma | muted (0.044) |
| Temperature | cool |
| Nearest name | Slate (#516572) |
| Black text | 3.33:1 |
| White text | 6.30:1 |
Values
| HEX | #40666B |
| RGB | rgb(64, 102, 107) |
| HSL | hsl(187, 25%, 34%) |
| OKLCH | oklch(48.4% 0.044 206.3) |
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 #40666B | 6.30:1 | AA | Lc -86.4 | Fine for body text |
| Black text on #40666B | 3.33:1 | AA large text | Lc 22.7 | Dividers and decoration only |
| #40666B text on white | 6.30:1 | AA | Lc 81.3 | Fine for body text |
| #40666B text on black | 3.33:1 | AA large text | Lc -20.5 | 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
#D1DBDD
oklch(88.4% 0.011 211)
-
Step 300
300
#B2C5C7
oklch(81% 0.021 204.4)
-
Step 400
400
#89A7AB
oklch(70.7% 0.034 206.4)
-
Step 500
500
#6B9196
oklch(63% 0.043 206.2)
-
Step 600
600
#527B81
oklch(55.5% 0.046 207.4)
-
Step 700
700 (this color)
#40666B
oklch(48.4% 0.044 206.3)
-
Step 800
800
#375559
oklch(42.8% 0.036 206.4)
-
Step 900
900
#304649
oklch(37.7% 0.028 206.6)
-
Step 950
950
#1C292B
oklch(27% 0.018 207.9)
#40666B 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) | #60636B | 0.043 |
| Deuteranopia (no green cones) | #595D6B | 0.041 |
| Tritanopia (no blue cones) | #2F6967 | 0.021 |
| Achromatopsia (no color) | #606060 | 0.044 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #40666B
#40666B
oklch(48.4% 0.044 206.3)
- #765552
#765552
oklch(48.4% 0.045 24.7)
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 #40666B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Slate #516572 ΔE 0.026
- Dark Aqua #05696B ΔE 0.038
- Deep Turquoise #017374 ΔE 0.048
- YInMn Blue #415A77 ΔE 0.048
- Dark Green Blue #1F6357 ΔE 0.048
- Dark Aquamarine #017371 ΔE 0.048
- Petrol #005F6A ΔE 0.051
- Dim Gray #696969 ΔE 0.057
Use #40666B 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.