As a designer, I have the privilege of going into a lot of different homes. Over the years I’ve observed a few common design pitfalls that homeowners succumb to but perhaps none more often than the woefully-small rug phenomenon.

Here are a few tips for identifying the right-sized rug for a few different rooms in your home:

Living room

Look for a rug large enough that at least the front legs of every chair and couch in the seating arrangement can be on it. In a standard-sized living room where some of the seating is against a wall, you will need at least an 8-by-10 rug to accomplish this. If you have a larger room where the furniture is floating away from the walls, plan on at least a 9-by-12. Do not, under any circumstances, buy a rug that goes just under your coffee table, what I call the “rug island.’’ If you happen to find a great (but too small) vintage rug, consider layering it over a more appropriately sized neutral sisal.

Bedroom

The right-sized rug for a bedroom clearly depends on the size of the bed, but aim for at least 24 inches of rug to extend beyond all sides. This gives you enough space to land on comfortably when you swing your feet out of bed. For a king-sized bed, that’s going to mean at least a 9-by-12 rug. If you can’t bear the thought of spending a lot on a large rug only to have most of it disappear under the bed, consider getting two runners, one for each side. They will still give something soft under foot but be a little kinder on your wallet.

Dining room

A rug in here needs to be large enough so that all of the chairs sit entirely on it, even when they are pulled out. Nothing is more annoying then trying to pull your chair up to a table only to have the back legs catch on the edge of a rug. To avoid this, aim for a rug that extends approximately 24 inches beyond the table on all sides.

Large rugs can be a financial commitment, but nothing makes a room like a perfect-sized one. It anchors a space, defines a seating area, and adds much-needed warmth and coziness underfoot.

Dina Holland is the founder and principal designer of Needham-based Dina Holland Interiors and the blogger behind Honey & Fitz. Submit your questions via Instagram by tagging her at @honeyandfitz. You can also e-mail them to Address@globe.com.