Square Footage Calculators | Free Construction Calculators
Calculate area and square footage
Room Area Calculator
Calculate room square footage
House Square Footage Calculator
Calculate total house area
Land Area Calculator
Calculate land area in various units
Roof Area Calculator
Calculate roof square footage
Wall Area Calculator
Calculate wall surface area
About Square Footage Calculations
Accurate square footage measurements are fundamental to construction, real estate, home improvement, and material estimation. Whether you're calculating flooring needs, estimating paint quantities, determining property values, or planning renovations, precise area calculations ensure you order the right amount of materials, budget accurately, and make informed decisions. Our professional square footage calculators handle rooms, entire houses, land parcels, roof surfaces, and wall areas with multiple shape options and unit conversions for any project size.
Why Use Our Square Footage Calculators?
Material Accuracy
Calculate exact flooring, paint, roofing, or siding quantities to avoid waste and ensure sufficient materials for complete coverage.
Cost Estimation
Determine project costs by multiplying square footage by per-unit prices for materials, labor, and contractor quotes.
Real Estate Valuation
Calculate livable space for property listings, appraisals, tax assessments, and price-per-square-foot comparisons.
Multiple Shape Support
Handle rectangular, L-shaped, circular, and irregular spaces with dedicated formulas for each configuration.
Unit Conversions
Easily convert between square feet, square yards, square meters, and acres for any calculation need.
Common Square Footage Calculations
Room Area for Flooring
Calculate floor space for hardwood, laminate, tile, or carpet ordering. Include waste factor (5-15%) for cuts and mistakes.
Total House Area
Sum all finished, heated living spaces for real estate listings, property valuations, and insurance documentation.
Land Parcel Measurements
Convert lot dimensions to square feet or acres for property surveys, development planning, and land value assessments.
Roof Surface Area
Calculate total roof area accounting for pitch, overhangs, and complexity to order shingles, underlayment, and estimate labor.
Wall Coverage
Determine paintable or tileable wall area subtracting doors, windows, and other non-covered surfaces for material quantities.
Multi-Room Projects
Calculate total square footage across multiple rooms or floors for whole-house renovation material planning and budgeting.
Frequently Asked Questions
How do I calculate square footage of a room?
Measure the length and width of the room in feet, then multiply: length × width = square feet. For a 12 ft × 15 ft room: 12 × 15 = 180 square feet. For irregular shapes, divide into rectangles, calculate each section separately, and add together. Always measure at the longest points and account for alcoves and recesses.
What is included in house square footage?
Finished, heated living space with ceilings at least 7 feet high is included. This covers bedrooms, bathrooms, kitchens, living rooms, finished basements with proper ceiling height, and enclosed porches. Excluded: garages, unfinished basements, attics without proper finishing, open porches, and rooms with ceilings under 5 feet. Standards vary by region and appraisal guidelines.
How do I convert square feet to acres for land?
Divide square feet by 43,560 (the number of square feet in one acre). For example: 87,120 sq ft ÷ 43,560 = 2 acres. Conversely, multiply acres by 43,560 to get square feet. One acre equals 208.71 feet × 208.71 feet square, or about 90% of a football field. Land measurements often use acres for parcels over 1 acre.
How do I calculate roof square footage for shingles?
Calculate ground floor area, then multiply by roof pitch factor. A simple gable roof is approximately: (length × width) × 1.3 for moderate pitch. For precise calculations, measure each roof plane separately accounting for pitch, overhangs, and dormers. Roof area is typically 15-30% more than ground floor area. Add 10% waste factor for shingle ordering.
How do I measure wall area for painting?
Measure wall length × height for each wall, add them together. Subtract door areas (20 sq ft each) and window areas (15 sq ft each). For a 12×15 ft room with 8 ft ceilings: (12+12+15+15) × 8 = 432 sq ft minus openings. One gallon of paint typically covers 350-400 sq ft per coat. Two coats are standard.
What is the difference between gross and net square footage?
Gross square footage includes all enclosed space including walls, measured to outer wall surfaces. Net (or usable) square footage excludes wall thickness, columns, and common areas, measuring only actual usable floor space. Real estate typically uses gross measurements. Commercial leases often specify net rentable square footage. The difference ranges from 10-25% depending on construction.
Measurement Best Practices
Always verify measurements on-site before ordering materials. Use a quality measuring tape or laser measure for accuracy. For real estate purposes, follow local appraisal standards and guidelines. When estimating materials, add appropriate waste factors: 5-10% for flooring, 10-15% for tile, 10% for shingles, and account for pattern matching in materials.