Cost Per Square Foot Calculator

Cost per square foot only compares like with like. A $45,000 job over 1,500 sq ft reads $30/ft², but that number changes completely depending on whether it includes demolition, permits, cabinetry, appliances, and finish grade. Before comparing, write down what each bid actually covers. A common trap is one contractor pricing the whole house footprint while the other prices only the rooms being touched. Normalize the scope first, then divide. If the two figures still differ by more than about 15–20%, the gap is usually materials grade or labor rate, not arithmetic.

Use one basis for every bid and say which one you used. Gross square footage measures to the outside of the exterior walls and includes hallways, closets, and stair openings. Finished or livable square footage — the ANSI Z765 basis most appraisers and MLS listings follow — excludes unfinished basements, garages, and attached but unheated space. Gross is commonly 5–10% larger than finished area on the same house, so a rate computed on gross always looks cheaper. For a remodel, the most useful basis is usually the area actually being worked on, not the whole house.

Fixed costs get spread. Mobilization, permits, dumpster rental, plan review, equipment delivery, and crew setup cost roughly the same whether you finish 200 sq ft or 2,000. A $2,000 block of permit and mobilization cost is $10/ft² on a 200 sq ft addition and $1/ft² on a 2,000 sq ft one. That is why small bathrooms routinely price at two to three times the per-foot rate of a whole-floor remodel, and why you should never scale a large-project rate down to a small job — the math will badly under-budget it.

Put both on one page and match them line for line. First, confirm the same square footage basis. Second, strip out anything only one bid includes — appliances, permits, temporary housing — and note it separately. Third, move owner-supplied materials into a common column. Fourth, divide each adjusted total by the same area. Enter the lower figure as the benchmark above and this calculator shows the per-foot gap plus what the higher-priced scope would cost at that rate. Then ask about the difference: a bid 30% below the others is usually missing scope, not cheaper.

Carpet and some commercial flooring are still quoted by the square yard, and one square yard equals nine square feet. So $4.50 per square foot is $40.50 per square yard — multiply by 9, never by 3. Sellers sometimes quote the yard price because the number reads smaller next to a per-foot competitor, so convert both to the same unit before comparing. Note that carpet ships in fixed 12 ft rolls, so the yardage you actually buy typically exceeds the yardage you calculated by 5–15% once seams and room shape are laid out.