In most living rooms, a rug that is slightly larger than the sofa looks better and ties the seating area together. A common rule is to have the front legs of the sofa and chairs resting on the rug, or at least touching it. This makes the space feel like a single, defined conversation zone.
Very small rugs that float in the middle, with all furniture outside, tend to look awkward – like a bathmat in a big room. They visually shrink the space instead of grounding it.
Of course, the exact size depends on your room. If the area is tight, at least aim for a rug that matches the sofa’s width or is just a little smaller, with the front legs on it. In large rooms, a big rug that fits all seating fully can look luxurious and intentional.
When in doubt, go a bit bigger instead of smaller, as long as it doesn’t crowd walls or doorways.