Square footage calculator

"Living area" typically excludes garages, unfinished basements, and outdoor spaces. "Total area" or "gross area" may include everything under roof. When comparing homes or pricing, confirm which definition applies.

Every extra square foot costs money to build ($100-$400), heat/cool ($1-$3/year), furnish ($20-$100 one-time), and maintain ($0.50-$2/year). A 3,000 sq ft home vs. 2,000 sq ft costs $50,000-$200,000 more to build and $1,000-$5,000 more annually to operate.

Furniture arrangement affects perceived size more than actual square footage. A 200 sq ft room with furniture pushed to walls feels larger than a 250 sq ft room with furniture blocking sightlines. Perceived space is about flow, not just area.

Office space often quotes "rentable" vs. "usable" square feet. Usable is your actual space; rentable includes common areas pro-rated across tenants. A 1,000 usable sq ft office might be quoted as 1,150 rentable sq ft.

Measure length and width in feet. Multiply them. A 12' × 14' room = 168 sq ft. For irregular shapes, break into rectangles, calculate each, and add together.

Measure each room separately and sum. Add 10% for simple rectangular rooms, 15% for complex layouts with angles or many doorways. Order slightly more than you calculate to account for cuts and mistakes.

Calculate wall area: (perimeter × wall height) − (window and door area). Divide by 350 sq ft (coverage per gallon). A 12' × 14' room with 8' ceilings: (52' × 8') − 50 sq ft for windows/doors = 366 sq ft ÷ 350 = 1.05 gallons per coat.

Bedroom: 120-150 sq ft comfortable, 200+ spacious. Living room: 150-200 sq ft minimal, 300+ spacious. Kitchen: 100-200 sq ft functional, 250+ with dining space. Master bathroom: 40-60 sq ft basic, 100+ luxurious.