Calculate area in square feet for any shape
Square footage is the standard way to measure area in the imperial system, and it remains widely used in the UK for property, construction, and home improvement. Whether you are measuring a room for new flooring, estimating the size of a garden, or comparing property listings, knowing the square footage gives you a concrete number to work with. In the UK, estate agents commonly quote property sizes in square feet alongside square metres. Understanding both units is important when browsing property portals, reading floor plans, or getting quotes from tradespeople. A room measuring 10 feet by 12 feet, for example, has an area of 120 square feet (approximately 11.15 square metres). This calculator handles four common shapes: rectangles, triangles, circles, and trapezoids, and automatically converts the result to square metres. Square footage calculations are essential for practical tasks like buying the right amount of paint, carpet, laminate flooring, or tiles. Getting the measurement wrong can mean costly returns or shortfalls. For irregular rooms, you can break the space into simpler shapes, calculate each separately, and add the results together.
To use the square foot calculator: 1. Select the shape that best matches the area you want to measure. For most rooms, "Rectangle / Square" is the right choice. Use "Triangle" for triangular sections, "Circle" for circular patios or pools, and "Trapezoid" for four-sided areas with two parallel sides of different lengths. 2. Enter the measurements in feet. For a rectangle, you need the length and width. For a triangle, enter the base (length) and height (width). For a circle, enter the radius. For a trapezoid, enter both parallel sides and the perpendicular height. 3. The calculator instantly displays the area in square feet, the equivalent in square metres, and the perimeter. Use the square metre value when you need metric measurements, such as for building regulations or European-standard materials. 4. For irregular or L-shaped rooms, calculate each section separately and add the square footage values together. Measure each section as a rectangle, triangle, or other shape, then combine the totals for the complete area.
The formulas used depend on the selected shape: Rectangle: Area = Length x Width Example: 10ft x 8ft = 80 ft2 Triangle: Area = 0.5 x Base x Height Example: 12ft base x 6ft height = 36 ft2 Circle: Area = Pi x Radius squared Example: Radius 5ft = 3.14159 x 25 = 78.54 ft2 Trapezoid: Area = (Side A + Side B) / 2 x Height Example: Sides 10ft and 6ft with height 4ft = (10 + 6) / 2 x 4 = 32 ft2 To convert square feet to square metres, divide by 10.7639. For example, 80 ft2 / 10.7639 = 7.43 m2. This conversion factor comes from the fact that one foot equals 0.3048 metres, so one square foot equals 0.3048 x 0.3048 = 0.0929 square metres. The perimeter is also calculated for each shape, which is useful when measuring for skirting boards, fencing, or edging materials.
When measuring rooms for practical purposes, always take multiple measurements and use the largest values to ensure you have enough material. Most tradespeople recommend adding 10% to 15% extra for waste, cuts, and pattern matching. For property valuation, square footage is measured according to the RICS (Royal Institution of Chartered Surveyors) code, which specifies measuring internal floor areas excluding walls. If you need to convert between feet and metres for height or length measurements, our Feet to Metres Converter provides exact results with decimals.