Too small, your existing furniture will dwarf it, and too large, it will look mismatched. The properly-sized coffee table pulls your room together.
Coffee tables are not one-size-fits-all; therefore, choosing them depends on the living room size and furniture setup.
Consider these basic rules of thumb:
1. Pick a table that's approximately the same height as your sofa cushions or slightly shorter.
2. It should measure no more than two-thirds of the sofa's total length.
3. Keep at least two feet of clearance around each table side.
After spending a little time with the measuring tape, you will have a range of sizes that will work; but don't ignore your designing impulses beyond the formula approach.