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Square footage calculator

Measure each room, add them up and see the total floor area in square feet and square metres – with extra for flooring and an optional cost estimate.

Measure in
RoomLengthWidthCounts
Total area
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With 10% extra for cutting
Total cost

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How to use the square footage calculator

  1. Choose feet or metres.
  2. Enter the length and width of each room. Add as many rooms as you need.
  3. Optionally enter a price per square foot (or per m²) – for flooring, paint or rent – to see the total cost.

The formula

Area = length × width

1 m² = 10.764 sq ft · 1 sq ft = 0.0929 m²

Worked example

A living room of 15 × 12 ft is 180 sq ft and a bedroom of 12 × 10 ft is 120 sq ft. Together that is 300 sq ft (27.87 m²). For flooring, add about 10% for cuts and waste: buy around 330 sq ft. At $4.50 per sq ft the floor area costs $1,350 before the extra.

Odd-shaped rooms

  • L-shaped rooms: split the room into two rectangles, measure each and add them as separate lines.
  • Triangles: area = ½ × base × height. Enter the base as length and half the height as width.
  • Circles: area = π × radius². A round room with a 5 ft radius is about 78.5 sq ft.

The Counts column lets you include an area at 50% or 25% – useful for spaces such as balconies or areas under a sloping roof when a contract or local rule counts them only partly.

For buying or renting, the official floor area may follow specific measuring rules (for example whether walls, stairs or unheated spaces are included). Check how your listing or contract defines it.

Frequently asked questions

How do I calculate square footage?
Multiply the length by the width in feet. A 12 × 14 ft room is 168 sq ft. For several rooms, calculate each one and add them together.
How many square feet is a square metre?
One square metre is 10.764 square feet. To convert sq ft to m², divide by 10.764.
How much extra flooring should I buy?
About 10% extra is usual for straight laying. For diagonal or herringbone patterns, 15% or more is safer.

Last reviewed: November 13, 2026

Results are estimates for general information only and are not financial, tax, medical or legal advice. Check important figures with a qualified professional.