Building materials calculators

Each calculator uses standard UK rules of thumb and shows the working, so you can check it. When you are happy with the list, send it for a delivered price.

• Brick calculator: Multiply the wall area by 60 for a single-skin wall or 120 for a one-brick wall, add about 5 percent, then allow roughly 1 tonne of building sand and 8 to 9 bags of cement per 1,000 bricks at a 1:4 mortar mix.
• Block calculator: Standard 440 × 215 mm blocks lay at 10 per square metre; multiply the wall area by 10, add about 5 percent, and allow roughly 0.008 to 0.01 m³ of mortar per square metre of 100 mm blockwork.
• Mortar calculator: Allow about 0.55 m³ of mortar per 1,000 bricks; at a 1:4 mix that is about 1 tonne of building sand and 8 to 9 bags of 25 kg cement.
• Concrete calculator: Concrete volume is length × width × depth; for a 1:5 mix allow about 15 bags of 25 kg cement and 2.2 tonnes of all-in ballast per cubic metre, plus a little extra for waste.
• MOT Type 1 calculator: Tonnes of MOT Type 1 = area × compacted depth × about 2.1, plus around 10 percent for compaction and levels; at 100 mm a tonne covers roughly 4.5 m².
• Sand and gravel calculator: For a sand and cement screed, area × depth gives the volume; allow about 1.6 tonnes of sharp sand per cubic metre and cement at your mix, typically 1:4. For gravel, allow about 1.5 tonnes per cubic metre.
• Plasterboard calculator: Divide the area by 2.88 m² (one 2400 × 1200 sheet), add about 10 percent for cutting, and allow around 30 to 40 drywall screws per sheet on walls.
• Insulation calculator: For loft rolls divide the area by the roll coverage for each layer (around 8 m² for 100 mm and 5 m² for 170 mm as a rough guide); for PIR boards divide the area by 2.88 m² per board and add 5 to 10 percent.