Determine where you are placing the rug. Area rugs are commonly placed underneath the edges of furniture to section seating areas off from the rest of a living room. Other rugs, however, may be placed in hallways or under dining and kitchen tables.
Measure the area you wish to place the rug. Leave the furniture in place as you take your initial measurements. Consider the furniture arrangement you wish to use in conjunction with the area rug. For a living room, measure the full area where the furniture sits, not just the area in between furniture.
Remove the furniture from the room or area, if applicable for the rug you wish to place. Removing the furniture gives you a better idea of the space you have available to work with.
Lay old newspapers on the floor to create the shape and size of the area rug you desire for the location. You may need to cut the newspapers to create a mock circular rug. Use masking tape to hold the sections of newspaper in place so you can move the rug around and get an idea of how the rug will look.
Replace your furniture while the fake newspaper rugs are still on the floor. Move the furniture around to get an idea of how the rug size will work with the furniture you have for that room. Remember that you are going to tire of a furniture arrangement after a while and other arrangements may not look good with certain rug measurements.
Write down the measurements you like most. Take these measurements with you to purchase the rug you need for your space.