How to use Square Footage Calculator
The square footage calculator computes the area of rooms, plots and irregular spaces in square feet, square metres, square yards and acres. It handles rectangles, triangles, circles, trapezoids and L-shaped rooms, and lets you add multiple areas together — useful for flooring, tiling, landscaping and real estate calculations.
- Select the shape of the space: rectangle, triangle, circle, trapezoid or L-shape.
- Enter the required dimensions.
- Add multiple rooms or sections using the "Add area" button.
- Review total area in all unit formats.
Your data never leaves your device — 100% private processing.
Area formulas for common shapes
Rectangle: length × width. Triangle: 0.5 × base × height. Circle: π × radius². Trapezoid: 0.5 × (a + b) × height. L-shape: split into two rectangles and sum. To convert: 1 sq yard = 9 sq ft; 1 sq metre = 10.764 sq ft; 1 acre = 43,560 sq ft. For flooring and tiling, always add 10–15% waste factor on top of the net area.
| From | To sq ft | To sq metres | To sq yards |
|---|---|---|---|
| 1 sq ft | 1 | 0.0929 | 0.111 |
| 1 sq metre | 10.764 | 1 | 1.196 |
| 1 sq yard | 9 | 0.836 | 1 |
| 1 acre | 43,560 | 4,047 | 4,840 |
Flooring and tiling — waste factors
Ordering flooring without waste factor leads to shortfalls that may require reordering from a different dye lot. Standard waste allowances: hardwood or laminate with straight lay — 10%; diagonal or herringbone lay — 15%; ceramic/porcelain tile (straight) — 10%; tile (diagonal) — 15%; carpet (with seaming) — 10–15%. Round up to the nearest standard roll or box size.
Worked examples
L-shaped room (12×10 + 6×4 ext.)
Inputs: 12×10 = 120 + 6×4 = 24 sq ft
Result: 144 sq ft total (+10% flooring waste ≈ 159)
Circular patio, 10 ft radius
Inputs: π × 10² = 3.1416 × 100
Result: ≈ 314 sq ft
Convert 80 m² listing to sq ft
Inputs: 80 × 10.764
Result: ≈ 861 sq ft
Glossary
- Dye lot
- A manufacturing batch; tiles or flooring from different lots may have slight colour variations.
- Net area
- The actual floor or wall area, excluding waste and overlap.
- Gross area
- Net area plus a waste factor — the amount to actually purchase.
- Linear foot
- A length measurement (1 foot long); different from square footage.
Related reading
Frequently Asked Questions
Why use Square Footage Calculator?
- Measure rooms and L-shaped spaces without manually splitting into sub-rectangles
- Add multiple room areas together for whole-floor flooring or landscaping projects
- Instantly convert between square feet, metres, yards and acres in one calculation
- Apply layout-specific waste factors before visiting the flooring store
Common use cases
- Calculate total floor area before ordering hardwood flooring for an open-plan level
- Measure a backyard plot in acres for a landscaping design and planting plan
- Work out the tile quantity needed for an L-shaped kitchen floor
- Determine paintable wall area across an entire room including the ceiling
- Convert a property listing's square metres to square feet when comparing homes
Get weekly tool tips & updates
New tools, power-user tips, and productivity hacks — delivered free every Friday.
No spam, ever. Unsubscribe with one click.
Related Construction
Concrete Calculator
Calculate how many bags or cubic yards of concrete you need for slabs, footings, and columns. Includes waste factor. Free concrete calculator.
Paint Calculator
Calculate how many gallons of paint you need for any room or surface. Accounts for doors, windows, and number of coats. Free paint calculator.
Mulch Calculator
Calculate how many cubic yards or bags of mulch you need for your garden or landscape. Enter area and desired depth to get exact mulch quantity needed.
Deck Board / Lumber Calculator
Calculate how many deck boards and how much lumber you need. Enter deck dimensions, board width, and spacing to get board count, lineal feet, and material cost.
Fence Calculator
Calculate fence posts, rails, and pickets needed for any fence. Enter fence length, post spacing, picket width, and rails per section to get all materials.
Tile Calculator
Calculate how many tiles you need for any room or surface. Enter room dimensions, tile size, and waste factor to get total tiles and square footage needed.
Explore all Construction.