Knowing your floor area is essential for buying flooring, estimating paint, comparing property listings and planning furniture layouts. Here is a complete measurement guide.
Rectangular Rooms
Area = length × width. Measure the longest and widest points, including any alcoves or bay windows that will be floored. For a 4.2m × 5.8m room: 4.2 × 5.8 = 24.36 m².
L-Shaped Rooms
Divide into two rectangles and add. Room 12ft × 10ft with a 6ft × 4ft extension: 12×10 = 120 sq ft; 6×4 = 24 sq ft; total = 144 sq ft.
Converting Square Metres to Square Feet
1 m² = 10.764 sq ft. Multiply m² by 10.764. A 50 m² flat = 538 sq ft. To reverse: multiply sq ft by 0.0929.
Quick reference: 20 m² = 215 sq ft. 50 m² = 538 sq ft. 80 m² = 861 sq ft. 100 m² = 1,076 sq ft. 200 m² = 2,153 sq ft.
How Much Flooring Do I Need?
Calculate room area, then add 10% for waste and cuts on straight-lay patterns. Add 15% for diagonal or herringbone patterns. For a 25 m² room: order 27.5 m² (straight) or 28.75 m² (diagonal). Always buy in whole packs and keep spares for future repairs.
How Much Paint Do I Need?
Calculate wall area: (2 × length + 2 × width) × ceiling height, minus door/window area. Standard coverage is 10–12 m² per litre for the first coat, 14–16 m² for second coat. A 4×5m room with 2.5m ceilings has approximately 45 m² of wall area — about 4–5 litres per coat.
Property Size Benchmarks
UK average 3-bed house: 85–95 m² (915–1,022 sq ft). London studio flat: 30–45 m². US single-family average: 186 m² (2,000 sq ft). Sydney apartment: 70–100 m². When comparing properties, always check m² or sq ft figures — photos can be deceptive.
Calculate area for any room shape in m² and ft².
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