Calculate the square footage of any room or area. Supports rectangular, circular, triangular, and trapezoidal shapes with instant conversions to sq yards, sq meters, and acres.
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13.3 sq yards
| Square Feet | 120 |
|---|---|
| Square Yards | 13.3 |
| Square Meters | 11.1 |
| Acres | 0.0028 |
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Most rooms are rectangular, making measurement straightforward. Use a tape measure or laser measure to find the longest wall (length) and shortest wall (width). Multiply these two numbers for square footage. A bedroom measuring 12 feet 6 inches by 10 feet 3 inches is 12.5 x 10.25 = 128.125 sq ft, typically rounded to 128 sq ft.
Always measure at floor level, not at the ceiling or midway up the wall. Measure from wall surface to wall surface, not baseboard to baseboard. For the most accurate results, measure each wall in at least two locations and use the average, as walls may not be perfectly parallel.
L-shaped rooms, bay windows, and alcoves require breaking the space into simple geometric shapes. Draw a rough floor plan and divide it into rectangles and triangles. Calculate each section separately and sum the results. For closets and built-in areas, measure and either include or exclude based on your purpose (real estate listings typically include closets).
Circular areas like bay windows or turret rooms use the formula: pi x radius squared. Measure the diameter and divide by 2 for the radius. A 6-foot diameter bay window alcove adds 28.3 sq ft to the room.
The most common errors are: measuring in inches instead of feet (divide inches by 12 to convert), forgetting to account for fixtures when measuring for materials (subtract cabinets, islands, built-ins), and confusing gross area with net area. For material calculations, subtract permanent fixtures but add 10% waste factor. For real estate listings, use gross interior dimensions including closets and hallways.
Understanding per-square-foot costs allows rapid budget estimation for any room. Painting costs $1.50-$3.50 per sq ft of wall area including labor and materials. For a 12x14 room with 8-foot ceilings, wall area is approximately 416 sq ft, costing $625-$1,450 to paint professionally.
Flooring varies dramatically by material: vinyl plank $3-$7/sq ft installed, laminate $4-$8/sq ft, hardwood $8-$15/sq ft, and tile $10-$20/sq ft. Carpet runs $3-$12/sq ft including padding and installation. For a 1,500 sq ft home, flooring replacement ranges from $4,500 (vinyl) to $22,500 (hardwood).
Not all square footage is created equal when renovating. Kitchen square footage costs $50-$350/sq ft due to cabinets, countertops, plumbing, and appliances. Bathroom renovation runs $75-$400/sq ft with waterproofing, tile, and fixtures driving costs. Living rooms and bedrooms are the cheapest at $15-$50/sq ft for paint, flooring, and trim.
When budgeting a whole-home renovation, calculate each room type separately. A 2,000 sq ft home with a 150 sq ft kitchen ($100/sq ft), 100 sq ft bathroom ($150/sq ft), and 1,750 sq ft living space ($25/sq ft) costs approximately: $15,000 + $15,000 + $43,750 = $73,750 total.
Multiply the room's length by its width in feet. A 12x14-foot room is 168 sq ft. For irregular rooms, break them into rectangles, calculate each area separately, and add them together. Always measure to the nearest inch for accuracy.
The median US home is approximately 2,014 sq ft according to US Census 2024 data. Small homes average 1,000-1,400 sq ft, medium homes 1,400-2,400 sq ft, and large homes 2,400-4,000+ sq ft. New construction averages 2,200-2,400 sq ft.
Divide square feet by 9. For example, 180 sq ft equals 20 sq yards. This conversion is commonly needed for carpet purchasing, which is often priced per square yard.
Use the formula: pi x (radius squared). For a 10-foot diameter circle: 3.14159 x (5 x 5) = 78.54 sq ft. Alternatively, use our calculator by entering the diameter and selecting the circle shape.
For real estate listings, square footage typically includes only heated/cooled living space above grade. Garages, unfinished basements, and attics are excluded. For material calculations (painting, flooring), measure all areas you plan to cover.
For material purchasing (tile, carpet, paint), measure to the nearest inch and add 10% waste. For real estate purposes, measure to the nearest foot. Professional appraisers measure to the nearest 6 inches. A laser measure ($30-$50) provides accuracy within 1/16 inch.
Divide the L-shape into two rectangles. Measure and calculate each rectangle separately, then add the areas together. For example, an L-shaped room might be a 10x12 section plus a 6x8 section = 120 + 48 = 168 sq ft.
Basic renovation costs $15-$30 per sq ft (paint, flooring, fixtures). Mid-range renovation runs $50-$100 per sq ft. High-end gut renovation costs $150-$350+ per sq ft. Kitchen and bathroom spaces cost 2-3x more per sq ft than living areas.
Rectangle: Length x Width
Circle: pi x (Diameter/2)^2
Triangle: (Base x Height) / 2
Trapezoid: ((Side A + Side B) / 2) x Height
Every formula on this page traces to a federal agency, central bank, or peer-reviewed institution. We cite the rule-makers, not secondhand blogs.
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Calculations are for educational purposes only. Consult a qualified financial advisor for personalized advice.