It’s not glamorous or glitzy, but an old-fashioned tape measure is one of the best tools you must ensure that the furniture you choose will fit in your room—and fit into your home. “Measurements are key,” says Mandy Neuman of Becker Furniture World in Becker, Minn. “By measuring before they shop, people can avoid a lot of problems on the back end, once the furniture is received.”

Here are the three areas of your home where taking accurate measurements are most important.

  • Scale Your Room

    Start by measuring the room where the furniture will go. Then run a tape measure over your existing furniture so you have an idea of sizes that work in the room. It’s easy to buy too much furniture if you haven’t noted these measurements, because items look smaller in a large showroom than they will in your home. Also measure other items that may affect furniture placement, such as built-in items and other permanent architectural details.

  • Don’t Forget the Ceiling

    Measure ceiling height and locations of lighting/fan fixtures, particularly in dining rooms and bedrooms. This will ensure you have room for the table and chairs to center under the lighting fixture while also including a buffet in the dining room—or that a canopy or poster bed will fit in the bedroom without bumping a ceiling fan or light, Neuman notes.

  • Evaluate Entryways

    You not only need to measure the rooms where the furniture will be placed, but also the spaces through which the furniture must pass to get there. That includes exterior and interior doorways, halls and stairwells—particularly if you live in an older home. “Older homes and farmhouse-style homes may have narrower doorways,” says Neuman. “Some homes have stairwells or turns that make it harder to bring in furniture.”