How do I calculate the area of an L-shaped room?

Split the L-shape into two rectangles, measure each one separately (length × width), then add them together. Our calculator does this automatically — just enter the dimensions of both rectangles. This method works for any room that can be divided into rectangular sections.

What is the area of a standard UK room?

A typical UK living room is around 15-20 m² (roughly 4m × 4.5m). A standard double bedroom is about 12-15 m², and a single bedroom is around 7-10 m². These are useful benchmarks when estimating materials for flooring, painting, or plastering.

How do I convert square metres to square feet?

Multiply the area in square metres by 10.764 to get square feet. For example, 10 m² = 107.64 ft². Our calculator shows both units automatically. This conversion is handy when working with American-sourced materials or older UK plans measured in imperial.

Do I need to add extra area for wastage?

This calculator gives you the pure mathematical area. For materials like tiles, flooring, or carpet, you should typically add 10% for wastage (cutting and fitting). For irregularly shaped rooms or diagonal laying patterns, add 15%. Use our specific material calculators for wastage-inclusive estimates.

How do I measure a room with bay windows or alcoves?

Break the room into simple shapes. Measure the main rectangular area first, then measure any bay windows or alcoves as separate rectangles or triangles and add them to the total. For a bay window, you can often approximate it as a trapezium (two parallel sides and a height).

TradeCalcs

Area Calculator — Calculate m² for Any Shape

Calculate the area of rectangles, triangles, circles, trapeziums, and L-shapes in square metres and square feet. Perfect for measuring rooms, patios, flooring, and more.

Shape

Select the shape you want to calculate the area of

Length

Width

How We Calculate This

This area calculator uses standard geometric formulas to compute the area of common shapes encountered in building and trade work. All measurements should be entered in metres and results are shown in both square metres (m²) and square feet (ft²).

Formulas used

Rectangle: Length × Width
Triangle: Base × Height ÷ 2
Circle: π × Radius²
Trapezium: (Side A + Side B) ÷ 2 × Height
L-Shape: Rectangle 1 area + Rectangle 2 area

Unit conversion

To convert from square metres to square feet, we multiply by 10.7639. This is the standard conversion factor used in the UK construction industry. One square metre equals approximately 10.76 square feet.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Verify with your supplier.