About

A free set of construction calculators covering concrete, rebar, masonry, finishes, earthwork, temporary works, unit conversion, areas and volumes, material weights, site planning, costing and building services — thirteen groups in all. No account, no login, no paywall.

Where the formulas come from

Every calculator page states the formula it uses and the assumptions behind it. The basis is current national standards and common trade practice: rebar weight follows the 0.00617d² rule in GB/T 1499.2, brick counts use a 240×115×53 mm unit with a 10 mm joint, and scaffolding material content comes from typical double-row tube-and-coupler layouts.

Local codes and estimating rules differ. Where a regional rule differs from the default here, the regional rule governs.

How your data is handled

All arithmetic runs in your browser. The numbers you type are never sent to a server, so we cannot see or store them. The calculators keep working offline.

Get in touch

Found a wrong result, want another calculator, or have a suggestion? There is no support desk here, but every message gets read — leave a note wherever you found this site. Arithmetic errors get fixed first.

Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.