Calculator Collections

Calculators grouped by project type. Pick your project and find every tool you need in one place.

Building an Extension

Every calculator you need for a house extension — foundations, structural, roofing, insulation and finishing.

Calculators for converting your loft — boarding, insulation, ventilation, structural and finishing trades.

Everything for a bathroom refit — tiling, plumbing, extraction, waterproofing and flooring.

Winter preparation in the right order: roof and gutter repairs, ventilation, insulation, draught-proofing and heating checks.

Build a timber stud partition with a door opening: frame, first fix, boarding, door lining and finishing in the right order.

A brick or block garden wall from foundations to coping: height rules, DPC, piers, movement joints and materials.

Excavation, sub-base, full mortar bed, edges and jointing in the right order, with the drainage and damp rules covered.