There is no single standard size for a living room area rug, but a collection of sizes. Standard sizes depend on the overall shape and type of the rug.
For area rugs, the standard sizes range between a small 3' x 5' rug, which is often for entryways, to the 9' x 12' rug, which is ideal for covering a large space. For a living room, a 7' x 10' area rug is good for underneath a coffee table in a small living room arrangement, while a 4' x 6' area rug fits underneath the coffee table only. Large area rugs, which are approximately 9' x 12' are used for larger living room arrangements.