Rug size finder
Leave a border of bare floor around the rug: 12 to 18 inches in most rooms, a little less in small ones.
Picture-hanging height
Gallery rule: the centre of the art sits 57 inches from the floor. Measure the drop from the top of the frame to the taut wire or hook.
Curtain rod & panels
Hang high and wide: the rod extends past the frame so open panels sit on the wall, not the glass.
Paint estimator
Two coats, about 350 square feet per gallon, minus doors and windows.
Dining table & clearance
Allow about 24 inches of table edge per diner and 36 to 42 inches from the table edge to the wall.
Chandelier size & height
Room length plus width in feet gives a starting diameter in inches. Over a table, use about half to two-thirds of the table width.
These are starting points, not specifications. Every room has its quirks. That is what a consultation is for.
Rules of thumb, not rules of law
Every number on this page comes from long-standing design practice: a 57-inch center line for art, at least 36 inches for a walkway, curtain panels two to two-and-a-half times the width of the rod. They work because they are built on human proportions: eye level, the width of a person walking, the length of a comfortable reach.
But rooms are not average. A 12-foot ceiling, a sloped attic, a window beside a fireplace, an antique that has to stay: these are where a designer earns her keep. Use the calculators to get close, then trust your eye. If your eye and the numbers disagree, the Journal explains the reasoning so you can decide which to follow.