#666A8A
Closest named color: Metallic Blue (#4F738E). oklch(53.3% 0.05 279), rgb(102, 106, 138).
Aa
White text reads best on this color (5.25:1).
About this color
#666A8A is a medium-dark, muted blue. In OKLCH its lightness is 53%, its chroma 0.050 and its hue 279°. Its hue sits on the cool side of the wheel. The nearest named color is Metallic Blue (#4F738E), ΔE 0.037 away. White text reads best on it, at 5.25:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | muted (0.050) |
| Temperature | cool |
| Nearest name | Metallic Blue (#4F738E) |
| Black text | 3.99:1 |
| White text | 5.25:1 |
Values
| HEX | #666A8A |
| RGB | rgb(102, 106, 138) |
| HSL | hsl(233, 15%, 47%) |
| OKLCH | oklch(53.3% 0.05 279) |
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 #666A8A | 5.25:1 | AA | Lc -81.5 | Fine for body text |
| Black text on #666A8A | 3.99:1 | AA large text | Lc 28.0 | Dividers and decoration only |
| #666A8A text on white | 5.25:1 | AA | Lc 76.1 | Fine for body text |
| #666A8A text on black | 3.99:1 | AA large text | Lc -25.6 | 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 600.
-
Step 50
50
#F5F5F7
oklch(97.1% 0.003 286.4)
-
Step 100
100
#E9E9EE
oklch(93.5% 0.007 286.3)
-
Step 200
200
#D7D8E2
oklch(88.4% 0.014 281.5)
-
Step 300
300
#BDBFCF
oklch(80.8% 0.022 280.2)
-
Step 400
400
#9B9FB8
oklch(70.8% 0.037 278.2)
-
Step 500
500
#8387A6
oklch(63.1% 0.047 279.2)
-
Step 600
600 (this color)
#666A8A
oklch(53.3% 0.05 279)
-
Step 700
700
#5B5E7B
oklch(49.1% 0.046 279.9)
-
Step 800
800
#4A4D64
oklch(42.7% 0.038 278.8)
-
Step 900
900
#3E4052
oklch(37.7% 0.031 279.8)
-
Step 950
950
#242630
oklch(27.1% 0.019 276.2)
#666A8A 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) | #616D8B | 0.010 |
| Deuteranopia (no green cones) | #5F6B89 | 0.011 |
| Tritanopia (no blue cones) | #5D7075 | 0.045 |
| Achromatopsia (no color) | #6C6C6C | 0.050 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #666A8A
#666A8A
oklch(53.3% 0.05 279)
- #746D4B
#746D4B
oklch(53.2% 0.05 97.9)
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 #666A8A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Metallic Blue #4F738E ΔE 0.037
- Battleship Gray #6C757D ΔE 0.045
- Grey Purple #826D8C ΔE 0.046
- Dull Blue #49759C ΔE 0.047
- Dusty Purple #825F87 ΔE 0.051
- Slate #516572 ΔE 0.051
- Dim Gray #696969 ΔE 0.052
- Stormy Blue #507B9C ΔE 0.053
Use #666A8A 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.