Square Footage Calculator

Calculate area in square feet from length and width — supports rectangles, triangles, and circles, multiple rooms, and any mix of feet, inches, yards, meters, or centimeters.

Length

Width

Unit

= 120.00 sq ft

Waste factor (%)Material order overage.Price per sq ft (optional)

Total area

120.00 sq ft

Square yards13.333 yd²

Square meters11.148 m²

Rooms / shapes1

Order with 10% waste132.00 sq ft

Per-shape subtotals appear next to each room above. Square footage is an area measurement — for volume, use Concrete Slab or Gravel.

Results update as you type

What this calculator does

This calculator converts each dimension to feet, applies the right shape formula, adds every room together, and outputs the total area in square feet, square yards, and square meters. It also scales by an optional waste percentage and an optional price per square foot.

Formula

Rectangle: area_ft² = length × width

Right triangle: area_ft² = ½ × base × height

Circle: area_ft² = π × radius²

Conversions: area_yd² = area_ft² ÷ 9 · area_m² = area_ft² × 0.092903

Variable definitions

length / width / base / height / radius — Dimensions of each room, converted to feet before applying the shape formula.
waste — Extra to order for material purchases, as a percent.
price — Cost per square foot for the optional material estimate.

Step-by-step calculation

Choose a shape and enter dimensions for each room.
The calculator converts each side to feet, applies the right formula, and sums every room.
Divide by 9 for square yards, or multiply by 0.092903 for square meters.
Apply the waste percentage to get the ordering quantity, then multiply by price per sq ft for the cost.

Worked example

An L-shaped living room split into two rectangles plus a circular rug area:

Room A: 12 ft × 10 ft = 120 sq ft
Room B: 8 ft × 6 ft = 48 sq ft
Round rug: π × 4² = 50.27 sq ft (excluded from flooring)

Floor total = 168 sq ft. With 10% waste, order 184.8 sq ft. At $4.50/sq ft: $831.60.

How to use this calculator

Pick a shape for the first room and enter the dimensions.
Click "Add room" to add more areas — different shapes and units are fine.
Adjust the waste percentage for material orders.
Enter a price per square foot for an optional cost estimate.

Common mistakes

Mixing units without converting: the calculator handles this when you select each room's unit — but always double-check.
Forgetting waste: ordering exact square footage almost always leaves you short.
Treating perimeter as area: 2 × (length + width) is perimeter, not square footage.

Frequently asked questions

›How do I calculate square footage?

Multiply length by width when both are in feet. For a room 12 ft × 10 ft: 12 × 10 = 120 square feet.

›How do I convert inches, yards, or meters to square feet?

Convert each side to feet first, then multiply. 1 inch = 1/12 ft; 1 yard = 3 ft; 1 meter ≈ 3.2808 ft. The calculator handles the conversion automatically.

›How do I calculate the square footage of an L-shaped or irregular room?

Split the area into rectangles, add each as a separate room in the calculator, and the totals combine automatically. Most irregular rooms can be broken into 2–3 rectangles.

›How many square feet are in a square yard or square meter?

1 square yard = 9 square feet. 1 square meter ≈ 10.7639 square feet.

›Why do flooring contractors recommend ordering extra?

Plan for 5%–15% extra to allow for cuts, waste, and pattern matching. Larger patterns and diagonal layouts need a higher overage.

›Can I estimate flooring cost?

Yes. Enter a price per square foot and the calculator multiplies by the total square footage (with waste) for a material-only estimate.

›How do I calculate the area of a circle or triangle room?

Use the shape selector. Circle = π × radius²; right triangle = ½ × base × height. The calculator returns the result in sq ft.