Construction Calculators

Fast, standards-based calculators for common construction tasks. Search for a calculator, or browse by category below.

Foundation

Concrete and rebar for strip, slab, pile and pad foundations, concrete mix proportions, floor slabs, formwork, excavation, drainage and frost depth.

Openings

Trim, casing, and other quantities for doors and windows.

Stairs

Riser heights, tread depths, stringer cut dimensions and landings for straight, L- and U-shaped stairs, concrete steps and baluster spacing.

Roof

Gable, hip, mono-pitch, mansard and flat roof areas, rafters and pitch, plus quantities of tiles, metal sheets, battens, underlay, gutters and downpipes.

Walls

Block and brick quantities for walls, including openings and waste.

Ceilings

Tile quantities and material estimates for ceiling coverings.

Floors

Tile quantities and material estimates for floor coverings.

Insulation

Board, framing and fixing quantities for ETICS and ventilated facades, plinths, attic floors and pitched roofs between rafters, plus the U-value of a wall or roof.

Heating

Heat loss, radiators, underfloor heating, expansion vessels, system water volume and yearly fuel use.

Electrical

Cable cross-sections and run lengths, voltage drop, power and current, sockets and switches, room lighting, appliance energy use and rooftop solar PV size.

Exterior

Material quantities for paving, kerbs, fences, gabions, retaining walls, gravel driveways, asphalt and lawns, plus bulk material mass, well rings and rainwater tanks.

Carpentry

Boards, joists, bearers, posts and fixings for timber structures such as decks.

Waterproofing

Membrane, coating, sealing tape, corner piece and collar quantities for wet rooms and below-ground foundation walls.

Finishing

Quantities for finishing work: putty, primer, timber lining and wood finishes, sealants, expanding foam and other finishing products, with packs rounded up.

Demolition

Debris volume, mass and container/skip counts for demolition and clearance work.

Ventilation

Supply and extract airflow for every room of a home, air change rate and the heat recovery unit capacity you need.

Area and volume

Room floor and ceiling area, wall area net of doors and windows, perimeter and volume – for rectangular, L-, T-, U-shaped or any custom outline.