The rug should take up the whole furniture space, however, if space allows, the best size rugs will also leave 12 to 18 inches of space around it for flooring to show. Choose a rug that's shape ...

The most common sizes for an area rug are 3 x 5-feet, 5 x 8-feet, 6 x 9-feet, 8 x 11-feet and 9 x 12-feet. A 12 x 15 size is also quite common, but it’s larger than most rooms can accommodate.