Coffee tables are the piece people most often buy by looks alone, and the piece where being two inches off is felt every single day. Four measurements do almost all the work.
Height: match the sofa seat
The tabletop should sit level with your sofa's seat cushion, or up to two inches below it. Reaching down for a mug should not require leaning. Most sofa seats land between 16 and 18 inches, so most coffee tables should too.
Taller tables read as dining furniture. Much lower and everything on the table disappears from view when you are sitting.
Length: about two thirds of the sofa
On an 84 inch sofa, look for a table around 50 to 56 inches long. Shorter than half the sofa looks lost in front of it. Longer than the sofa itself makes the seating look undersized.
Gap: 14 to 18 inches
This is the one people get wrong. Leave 14 to 18 inches between the front edge of the sofa and the table. Close enough to set a glass down without standing, far enough to get past without turning sideways. Below 12 inches the room feels cramped. Above 20 and the table stops being reachable.
Walkways: 30 to 36 inches
Around the outside of the arrangement, leave 30 to 36 inches for main paths through the room, and at least 18 inches for a secondary route. If a path is going to be walked daily, use the higher number.
Picking a shape
- Rectangular for long sofas and rectangular rooms. The default for a reason.
- Round or oval for tight spaces, high traffic paths, and homes with small children. No corners to catch a hip or a forehead.
- Two smaller tables for L shaped sectionals. One table almost never serves both runs well, and a pair lets you move them apart when people come over.
A quick test before you buy
Tape the table's footprint on the floor with painter's tape and leave it a few days. Walk the room normally. If you clip the tape with your foot on the way to the kitchen, it is too big, no matter how good it looked in the photo.