It can be confusing when trying to figure out what size rug to use for different furniture groupings. This read will give you a better understanding of how to place your rug, and what size to use.
For dining room tables you need to know the dimension around the table with the chairs all the way pulled out. There should be ample room of rug under the dining table and chairs. When the chairs are pulled out, they should remain on the rug. A rug that does not reach the chairs when pulled out, will look wrong for the space. An easy way to get the dimensions needed is by measuring all four sides of the table with the chairs pulled out, enough to be seated. Take the diameter measurement for round dining room table and chairs.
In a formal living room the seating groups should be on the rug, with ample room around the grouping for walking traffic. The only time when this rule can be broken is when a rug is placed in front of a sectional sofa.
Sectionals are typically used in a more casual setting. Place the rug in front of the sectional with the rug slightly under the front legs of the sofa. In this situation a smaller area rug can be simply placed in front of the sectional if necessary.
Runners that are leading down a hallway should have at least 3-6 inches of open floor space on either side of the rug. If the hallway is not wide enough to have space on either side, select a narrow runner. They can be found!
Smaller accent rugs can be placed on either side of a bed. This will allow for under foot comfort when getting out of bed on chilly mornings. This is especially nice if the bedroom flooring is not carpet. Make sure that the rug is not a tripping hazard when using smaller accent rugs.
A general rule of thumb is to place a seating group in the middle of an area rug, and make sure there is enough rug area for foot traffic to walk around on.