Square Footage Calculator
Calculate square footage for any shape — rectangle, triangle, circle, or L-shape. Enter dimensions in feet for instant results in sq ft, sq meters, and sq yards.
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Enter your values above to see the results.
Tips & Notes
- ✓Measure from inside wall to inside wall — outside dimensions overestimate usable floor area by 8-12 inches per wall pair due to wall thickness.
- ✓For irregular spaces, divide into simple rectangles or triangles, calculate each section separately, and add the results together.
- ✓When ordering flooring or tiling, always add a waste factor to your calculated area: 10% for straight patterns, 15% for diagonal, 20% for herringbone.
- ✓For circular spaces (round patios, curved planters), the radius is half the diameter. A 12-foot diameter circle has a 6-foot radius and area = π × 6² = 113.1 sq ft.
- ✓1 square meter = 10.764 sq ft. Use this when comparing with materials sold per square meter — multiply your sq ft result by 0.0929 to convert.
Common Mistakes
- ✗Entering wall length instead of floor width — the floor is what you are measuring, and inside dimensions are smaller than the outside wall span.
- ✗Using diameter instead of radius for circular areas — radius = diameter ÷ 2. A 20-foot diameter pool has a 10-foot radius and area of 314 sq ft, not 1,257 sq ft.
- ✗Forgetting the waste factor when ordering materials — the calculated square footage is the minimum; always order more to account for cuts and breakage.
- ✗Mixing feet and meters in the same calculation — enter all dimensions in the same unit. Convert measurements before entering if needed.
- ✗Calculating area without accounting for obstacles — large fixed fixtures, built-in cabinets, or columns reduce the actual area needing material.
Square Footage Calculator Overview
Square footage is the most fundamental measurement in home improvement, real estate, and construction. Accurate area calculation is the starting point for every flooring, tiling, painting, landscaping, and HVAC project.
Area formulas by shape:
Rectangle: A = L × W | Triangle: A = 0.5 × B × H | Circle: A = π × r² ≈ 3.14159 × r²
EX: Circular patio with 8 ft radius → A = 3.14159 × 8² = 3.14159 × 64 = 201.06 sq ft → Add 10% waste for pavers → Order 221 sq ft worth of materialArea unit conversion table:
| Square Feet | Square Meters (m²) | Square Yards | Square Inches | Acres |
|---|---|---|---|---|
| 1 sq ft | 0.0929 m² | 0.111 sq yd | 144 sq in | 0.0000230 ac |
| 100 sq ft | 9.29 m² | 11.11 sq yd | 14,400 sq in | 0.002296 ac |
| 500 sq ft | 46.45 m² | 55.56 sq yd | 72,000 sq in | 0.01148 ac |
| 1,000 sq ft | 92.90 m² | 111.1 sq yd | 144,000 sq in | 0.02296 ac |
| 43,560 sq ft | 4,047 m² | 4,840 sq yd | — | 1 acre |
| Project | Formula | Waste Add-On | Example (200 sq ft room) |
|---|---|---|---|
| Hardwood flooring | Sq ft ÷ coverage per box | +10% | 220 sq ft → 11 boxes (20 sq ft/box) |
| Ceramic tile (12"×12") | Sq ft × 1.1 (straight lay) | +10% | 220 tiles needed |
| Carpet | Sq ft ÷ 9 = sq yards | +10% | 200 sq ft ÷ 9 × 1.1 = 24.4 sq yd |
| Paint (walls only) | Wall area ÷ coverage/gal | +15% (2 coats) | Calculate wall area separately |
| Sod / turf | Area in sq ft ÷ roll size | +5% | 210 sq ft ÷ 10 sq ft/roll = 21 rolls |
Frequently Asked Questions
Measure the room length and width in feet from inside wall to inside wall. Multiply length × width. Example: 13 ft × 15 ft = 195 sq ft. For L-shaped rooms, divide into two rectangles: measure the first section (e.g., 13'×10' = 130 sq ft) and the second section (e.g., 8'×7' = 56 sq ft) and add them: 130 + 56 = 186 sq ft. Use a metal tape measure and measure twice for accuracy before purchasing flooring or other materials.
Multiply square feet by 0.0929 to get square meters. To convert square meters to square feet, multiply by 10.764. Quick reference: 100 sq ft = 9.29 m²; 200 sq ft = 18.58 m²; 500 sq ft = 46.45 m²; 1,000 sq ft = 92.9 m². Most European building materials are specified in square meters — use this conversion to determine quantities when purchasing tile, flooring, or insulation sold per m².
Area = 0.5 × base × height. The base is the longest side of the triangle; the height is the perpendicular distance from the base to the opposite corner — not the length of the slanted side. Example: a triangular corner room with a 14-foot base and 10-foot perpendicular height = 0.5 × 14 × 10 = 70 sq ft. For irregular triangles, measure the base along the longest wall and use a square or level to find the perpendicular height from that base to the opposite corner.
Familiar reference sizes: one standard parking space = 160 sq ft (8'×20'); a single-car garage = 200-240 sq ft; a typical US master bedroom = 200-250 sq ft; a standard high school basketball court = 4,700 sq ft; a football field (without end zones) = 48,000 sq ft = 1.1 acres. For home sizing: a 500 sq ft studio apartment is small but livable; 1,000 sq ft houses 2-3 people comfortably; 2,000 sq ft is a typical 3-bedroom American home; 3,000+ sq ft is large by global standards.
One acre = 43,560 sq ft. An acre is roughly the size of a football field including end zones (about 48,400 sq ft). A square acre would be approximately 208.7 feet on each side. Common land measurements: a standard residential lot in the US is 6,000-10,000 sq ft (0.14-0.23 acres); a quarter-acre lot is 10,890 sq ft; a half-acre is 21,780 sq ft. To convert sq ft to acres, divide by 43,560.
Residential square footage in real estate typically counts all finished, heated, and cooled interior space. This includes bedrooms, bathrooms, kitchen, living areas, and finished basements (in some markets). It excludes unfinished basements, garages, covered porches, and unheated spaces. Measure each room's interior floor area, add all rooms together. Include hallways, closets, and stairwells in the total. Real estate square footage is usually measured from inside wall to inside wall on the exterior-most walls. Practices vary by market — some include exterior wall thickness in the measurement.