#666F8A
Closest named color: Metallic Blue (#4F738E). oklch(54.4% 0.044 270.5), rgb(102, 111, 138).
Aa
White text reads best on this color (4.99:1).
About this color
#666F8A is a medium-dark, muted blue. In OKLCH its lightness is 54%, its chroma 0.044 and its hue 270°. Its hue sits on the cool side of the wheel. The nearest named color is Metallic Blue (#4F738E), ΔE 0.030 away. White text reads best on it, at 4.99:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | muted (0.044) |
| Temperature | cool |
| Nearest name | Metallic Blue (#4F738E) |
| Black text | 4.20:1 |
| White text | 4.99:1 |
Values
| HEX | #666F8A |
| RGB | rgb(102, 111, 138) |
| HSL | hsl(225, 15%, 47%) |
| OKLCH | oklch(54.4% 0.044 270.5) |
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 #666F8A | 4.99:1 | AA | Lc -79.9 | Fine for body text |
| Black text on #666F8A | 4.20:1 | AA large text | Lc 29.5 | Dividers and decoration only |
| #666F8A text on white | 4.99:1 | AA | Lc 74.5 | Content text, not long reading |
| #666F8A text on black | 4.20:1 | AA large text | Lc -27.2 | 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
#E8EAEE
oklch(93.7% 0.006 264.5)
-
Step 200
200
#D6D9E1
oklch(88.5% 0.011 269.5)
-
Step 300
300
#BCC0CE
oklch(80.9% 0.02 273.2)
-
Step 400
400
#99A0B5
oklch(70.7% 0.032 270.9)
-
Step 500
500
#8089A3
oklch(63.2% 0.041 270.2)
-
Step 600
600 (this color)
#666F8A
oklch(54.4% 0.044 270.5)
-
Step 700
700
#586078
oklch(49.1% 0.04 270.5)
-
Step 800
800
#484E62
oklch(42.6% 0.034 271.8)
-
Step 900
900
#3C4150
oklch(37.7% 0.027 270.6)
-
Step 950
950
#23262F
oklch(26.9% 0.017 270.7)
#666F8A 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) | #67718B | 0.006 |
| Deuteranopia (no green cones) | #646E89 | 0.004 |
| Tritanopia (no blue cones) | #5D7478 | 0.039 |
| Achromatopsia (no color) | #6F6F6F | 0.044 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #666F8A
#666F8A
oklch(54.4% 0.044 270.5)
- #7A6F53
#7A6F53
oklch(54.4% 0.043 89.1)
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 #666F8A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Metallic Blue #4F738E ΔE 0.030
- Battleship Gray #6C757D ΔE 0.032
- Grey Blue #647D8E ΔE 0.040
- Dull Blue #49759C ΔE 0.042
- Stormy Blue #507B9C ΔE 0.043
- Battleship Grey #6B7C85 ΔE 0.043
- Grey Purple #826D8C ΔE 0.043
- Purple Grey #866F85 ΔE 0.049
Use #666F8A 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.