What is the 2/3 rule for living rooms?
The 2/3 rule is a proportion guideline for furniture sizing: your coffee table should be about 2/3 the length of your sofa, your rug should cover at least 2/3 of the seating area, and your curtains should be hung 2/3 of the way between the window frame and ceiling.
This rule creates visual balance without being too matchy or rigid. For example, if your sofa is 84 inches long, your coffee table should be roughly 56 inches. If it's exactly the same length — or much shorter — the proportions feel off.
The 2/3 rule also applies to art above a sofa: the piece (or grouping) should span about 2/3 of the sofa width. Too small and it looks lost; too wide and it overwhelms.