Square Footage Calculator
Calculate the area of rectangular rooms, circular spaces, and triangular shapes. Enter measurements in feet or metres — the result is shown in both square feet and square metres.
How Square Footage Calculator works
Rectangle area
The area of a rectangle is length × width. For a room that is 12 feet long and 10 feet wide, the area is 120 square feet (about 11.1 m²). Always measure at the longest and widest points and deduct for any alcoves or protrusions if calculating floor covering requirements. Rooms are rarely perfect rectangles, so measure each section separately and add the totals.
Circle area
The area of a circle is π × radius². For a circular space with a radius of 5 feet, the area is π × 25 ≈ 78.5 sq ft. To find the radius, measure across the widest point (the diameter) and halve it. Circle area calculations appear in flooring for round rooms, garden design (circular lawns or patios), and calculating the surface area of cylindrical structures.
Triangle area
The area of a triangle is ½ × base × height. The height must be measured perpendicular to the base — not along a slanting side. For a triangular alcove with a base of 8 feet and a perpendicular height of 6 feet, the area is 0.5 × 8 × 6 = 24 sq ft. Irregular rooms can often be divided into triangles and rectangles to get an accurate total.
Converting between square feet and square metres
One square metre equals approximately 10.764 square feet, and one square foot equals 0.0929 square metres. UK estate agents traditionally quote floor areas in square feet; European and international standards use square metres. The conversion factor is the square of the linear factor: 1 foot = 0.3048 m, so 1 sq ft = 0.3048² = 0.0929 m².
Frequently asked questions
How do I measure square footage of a room?
Measure the length and width of the room at their longest and widest points, then multiply. For an L-shaped room, split it into two rectangles, calculate each area separately, and add them. Measure in feet for square feet, or metres for square metres. Use the calculator above to handle the conversion automatically.
How many square feet are in a square metre?
One square metre is approximately 10.764 square feet. Conversely, one square foot is approximately 0.0929 square metres. So a room of 150 sq ft is about 13.9 m², and a room of 20 m² is about 215 sq ft.
What is the formula for the area of a circle?
Area = π × r², where r is the radius and π ≈ 3.14159. To find the radius, measure the diameter (across the widest point) and divide by two. For a circle with diameter 10 feet, radius = 5 feet, area = π × 25 ≈ 78.5 sq ft.
How much flooring do I need for a room?
Calculate the area using this tool, then add 10–15% for cutting waste, pattern matching, and future repairs. For carpet, the figure given by this tool is a good starting point. For tiles or wood planks, measure any irregular shapes separately, divide into rectangles or triangles, and sum the areas.
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