How it works
Area of a rectangle is length × width. For a room measured in feet, square footage = length(ft) × width(ft). To convert to square metres, multiply square feet by 0.092903 (since 1 ft = 0.3048 m, 1 sq ft = 0.092903 sq m exactly). Worked example: 12 ft by 15 ft room. Area = 12 × 15 = 180 sq ft. In metric: 180 × 0.092903 = 16.72 sq m. Flooring and paint estimates start from this area — add 5–10% waste factor for cuts and pattern matching on tile or hardwood. Irregular rooms divide into rectangles (and triangles for alcoves), sum the areas, or use exterior dimensions minus wall thickness for rough estimates. Ceiling area equals floor area in flat rooms — useful for paint on ceilings. Commercial leasing sometimes quotes rentable square feet including common-area allocations; this calculator measures simple interior rectangles only. If you measured in inches, convert first: inches ÷ 12 = feet, then multiply. Carpet and vinyl often sell by the square yard (divide sq ft by 9). Re-run the tool for each room and add results when estimating a whole floor.
Formula
sq ft = length × width | sq m = sq ft × 0.092903
Tips
- Measure wall-to-wall at the longest points — alcoves add area beyond a simple rectangle guess.
- Add 10% to flooring orders for cuts, defects and future repairs.
- One gallon of paint covers roughly 350–400 sq ft per coat — divide your area accordingly.
- For L-shaped rooms, split into two rectangles and add their areas.
Frequently asked questions
- How many square feet is a 12×15 room?
- 180 sq ft (12 × 15). That is approximately 16.72 square metres.
- How do I convert sq ft to sq m?
- Multiply by 0.092903. 180 sq ft × 0.092903 = 16.72 sq m.
- Does this work for yards?
- Enter dimensions in feet. If you measured in inches, divide by 12 first (144 sq in = 1 sq ft).
- How much flooring do I need for 180 sq ft?
- Order at least 180 sq ft plus 10% waste ≈ 198 sq ft. Check box coverage — cartons list sq ft per box.