Square Footage Calculator

To calculate square footage of a rectangular room, measure the length and width in feet, then multiply these dimensions together. For example, a bedroom measuring 12 feet long by 10 feet wide equals 120 square feet (12 × 10 = 120). Always measure at the widest points and include closets and alcoves in your measurements. For irregular shapes, divide the room into smaller rectangular sections, calculate each area separately, then add them together for the total square footage. This is fundamentally a multiplication calculation similar to how you'd calculate other proportions.

Calculate your room's square footage using length times width, then add 10% extra for waste and cutting. For instance, if your room is 200 square feet, order 220 square feet of flooring material (200 × 1.10 = 220). This extra material accounts for cuts around doorways, corners, and any installation mistakes. For tile or patterned flooring that requires precise matching, consider adding 15% instead of 10%. Use our unit converter if your flooring is sold in square meters or square yards.

To calculate wall area for painting, measure each wall's length and height, multiply to get square footage, then add all walls together. For example, a 12×10 foot room with 8-foot ceilings has approximately 352 square feet of wall space: (12+12+10+10) × 8 = 352 sq ft. Subtract approximately 20 square feet for each standard door and 15 square feet for each window. One gallon of paint typically covers 350-400 square feet, so this room would need about one gallon for one coat, or two gallons for two coats.

Square feet and square yards both measure area, but one square yard equals exactly 9 square feet (3 feet × 3 feet). Carpet is often priced per square yard, while rooms are typically measured in square feet. To convert square feet to square yards, divide by 9. For example, a 270 square foot room equals 30 square yards (270 ÷ 9 = 30). Always confirm which unit your carpet supplier uses for pricing to avoid ordering errors. Our calculator provides automatic conversions between square feet, square yards, square meters, and acres.

For irregular rooms, break the space into smaller rectangular or triangular sections, calculate each section's area, then add them together. For example, an L-shaped room can be divided into two rectangles: if one section is 10×12 feet (120 sq ft) and the other is 6×8 feet (48 sq ft), the total is 168 square feet. For circular or curved areas, use our circle calculator with the radius measurement. Use our calculator's "Add to Total Area" button to combine multiple room sections easily and maintain an accurate running total.

Real estate square footage often includes only heated and finished living space, excluding garages, unfinished basements, and outdoor areas. Measurement standards also vary: some measure exterior walls (gross living area) while others measure interior dimensions (net living area). Professional appraisers follow specific guidelines that may differ from simple length × width calculations. Additionally, vaulted ceilings, stairwells, and areas with ceiling heights below 7 feet may be counted differently or excluded entirely. Always verify the measurement method used in your area's real estate market.

One acre equals exactly 43,560 square feet. To convert square feet to acres, divide the square footage by 43,560. For example, a lot measuring 10,890 square feet equals 0.25 acres (10,890 ÷ 43,560 = 0.25). Common residential lot sizes include quarter-acre (10,890 sq ft), half-acre (21,780 sq ft), and one-acre (43,560 sq ft) lots. Our calculator automatically displays conversions in acres, square feet, square meters, and square yards so you can easily compare measurements regardless of how the land is described.

Yes, you can calculate square footage from inch measurements by either converting to feet first or using our calculator's inch input option. To convert manually, divide inches by 12 to get feet. For example, a space measuring 144 inches by 120 inches converts to 12 feet by 10 feet (144÷12=12, 120÷12=10), which equals 120 square feet. Alternatively, simply select "Inches" from our input unit dropdown, enter your measurements directly, and the calculator will automatically convert and display the result in square feet and other units.

For flooring projects, measure to the nearest inch for best results. Small measurement errors multiply when calculating area, so a 1-inch error on a 12-foot wall becomes a 12-square-inch discrepancy. Round up measurements to the next inch rather than down to ensure adequate material. For large spaces over 500 square feet, being accurate within 2-3% is generally acceptable since you should add 10-15% extra for waste anyway. However, for expensive materials like hardwood or tile, precise measurements save money and reduce waste. When budgeting for materials, use our discount calculator to factor in bulk purchase savings or contractor discounts.

Calculate each room individually, then use our "Add to Total Area" button to maintain a running total of your entire house. Measure bedroom, living room, kitchen, bathrooms, and hallways separately for accuracy. For example, if you have a 150 sq ft bedroom, 200 sq ft living room, and 100 sq ft kitchen, click "Add to Total" after each calculation to see your combined 450 square feet. This feature is especially useful for real estate listings, HVAC sizing, or whole-house flooring projects where you need the cumulative area of multiple spaces.