Square Footage Calculator
Calculate area for rectangles, circles, triangles, and more shapes
How to Use This Square Footage Calculator
- Select the shape of your area (rectangle, circle, triangle, etc.)
- Choose your measurement unit (feet, inches, meters, etc.)
- Enter the required dimensions for your selected shape
- Optionally enter quantity for multiple identical areas
- Add price per square foot for cost estimates
- Click Calculate to see area in multiple units plus cost
Example: A 12×15 foot room = 180 sq ft. At $4.50/sq ft for hardwood flooring, materials cost $810. With 10% extra for waste, order enough for 198 sq ft ($891).
Tip: For irregular rooms, divide into simple shapes, calculate each separately, then add them together. An L-shaped room becomes two rectangles.
Why Use a Square Footage Calculator?
Accurate square footage calculations are essential for buying materials, comparing property values, and estimating project costs.
- Calculate flooring materials needed (hardwood, carpet, tile, laminate)
- Estimate paint coverage (one gallon covers about 350-400 sq ft)
- Compare real estate prices per square foot
- Determine mulch or gravel quantities for landscaping
- Calculate sod or seed amounts for lawn installation
- Estimate rental costs when charged by square foot
Understanding Your Results
Results show area in square feet and square meters with conversions to other common units.
| Result | Meaning | Action |
|---|---|---|
| Under 100 sq ft | Small space (bathroom, closet) | Material packages often oversized - buy minimum quantities |
| 100-400 sq ft | Medium room (bedroom, office) | Standard project size; one day for most flooring installs |
| 400-1000 sq ft | Large room or small apartment | May need material delivery; multi-day project |
| Over 1000 sq ft | Large area (whole floor, yard) | Bulk pricing may apply; coordinate staging and delivery |
Meaning: Small space (bathroom, closet)
Action: Material packages often oversized - buy minimum quantities
Meaning: Medium room (bedroom, office)
Action: Standard project size; one day for most flooring installs
Meaning: Large room or small apartment
Action: May need material delivery; multi-day project
Meaning: Large area (whole floor, yard)
Action: Bulk pricing may apply; coordinate staging and delivery
Note: Always add 10% for waste on flooring projects. For diagonal or herringbone patterns, add 15-20%. Keep leftover materials for future repairs.
About Square Footage Calculator
Formula
Rectangle: L×W | Circle: πr² | Triangle: ½bh | Trapezoid: ½(b₁+b₂)h These formulas give area in squared units of your input measurements. 12 feet × 10 feet = 120 square feet. Convert to square meters by dividing by 10.764.
Current Standards: Real estate measurement standards (ANSI Z765) specify what counts toward gross living area. Generally, living space must be heated, finished, and directly accessible. Below-grade space often listed separately.
Frequently Asked Questions
How do I measure an irregularly shaped room?
Divide it into rectangles, triangles, or circles that you can measure. For an L-shaped room, measure two rectangles and add them. For rooms with bay windows, add the bump-out rectangle. For curved areas, approximate with a semicircle (½πr²). Always use the largest dimensions for each section.
How do I calculate square footage from dimensions in inches?
Calculate in inches then divide by 144 (there are 144 square inches in a square foot). Or convert dimensions to feet first: divide each measurement by 12, then multiply. A 48×36 inch area = 48/12 × 36/12 = 4 × 3 = 12 square feet.
How much flooring should I order beyond my square footage?
Add 10% for standard installations to account for cuts, waste, and defects. Add 15% for diagonal patterns. Add 20% for herringbone or complex layouts. Also order an extra box for future repairs - matching product later may be impossible.
How do I measure for paint?
Calculate wall square footage: perimeter × height. A 12×14 room with 8-foot ceilings has 52 feet of perimeter × 8 feet = 416 sq ft of wall. Subtract about 20 sq ft per door and 15 sq ft per window. One gallon covers 350-400 sq ft; two coats means dividing coverage in half.
Why do real estate listings sometimes show different square footage?
Measurement methods vary. Some include garages, others don't. Finished basements may or may not count. Exterior measurements (measuring outside walls) give larger numbers than interior measurements. Tax records, appraisals, and listings might all differ. Verify the measurement method for accurate comparisons.