Home renovation calculator for Mac, Windows and Linux

Measure once, then type the room: Ratio turns square metres into litres, bags and boxes, and keeps the units so you can check them.

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Materials

3 m * 4 m12 m²
paint 40 m2 2 coats8 L
paint 40 m2 2 coats at 12 m2/l6.7 L
tiles 12 m213.2 m²
tiles 12 m2 + 15%13.8 m²
concrete 2 m3184
20 m2 in sq ft215.28 ft²

Paint covers 10 m² a litre unless you say otherwise; tiles get 10% for cuts and breakage; concrete counts 25 kg bags of ready mix (“concrete 2 m3 in 40 kg bags”).

Buying and renting

mortgage 300k with 20% down at 5% for 30 years1,288.3719
loan 240k at 5% for 30 years1,288.3719
rental yield 1200/month on 250k5.76%

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Questions

How much paint do I need? Area × coats ÷ coverage: “paint 40 m2 2 coats” gives 8 litres at 10 m² a litre. Add “at 12 m2/l” for the coverage on your tin.

How many bags of concrete for a cubic metre? About 92 bags of 25 kg, counting 2,300 kg of dry mix per m³. Check the bag: yields vary by brand.

Can it include the down payment? Yes: “mortgage 300k with 20% down at 5% for 30 years” borrows 240k. A fixed amount works too: “with 60k down”.