All calculators
Every tool on the site, grouped by trade. Each one shows its formula, a worked example and the assumptions it makes.
Concrete
Volume, slabs, footings and bag counts for concrete work, with editable density and wastage.
- Concrete Volume Calculator Work out the volume of concrete needed for a rectangular pour, with an allowance for wastage.
- Concrete Slab Calculator Size a floor or ground slab: volume, ready-mix load, weight and area, including an edge thickening if there is one.
- Concrete Footing Calculator Calculate concrete for strip footings or a set of identical pad footings.
- Concrete Bags Calculator Convert a concrete volume into the number of pre-mixed bags needed, for small pours where ready-mix is not practical.
Road & Asphalt
Asphalt tonnage, granular base, tack coat and prime coat, with density under your control.
- Asphalt Tonnage Calculator Convert a paving area and layer thickness into tonnes of asphalt, using a density you control.
- Road Base & Subbase Calculator Calculate compacted volume and delivered tonnage of granular base or subbase, including the bulking allowance between loose and compacted material.
- Tack Coat Calculator Calculate bitumen emulsion for a tack coat, accounting for dilution and residue content to give the binder actually left on the road.
- Prime Coat Calculator Calculate prime coat quantity for a granular base, including sand blinding if it is used.
Earthwork
Excavation, backfill and trench volumes, including swell and compaction shrinkage.
- Excavation Calculator Calculate excavation volume in bank measure and the swelled volume that has to be hauled away.
- Backfill Calculator Calculate backfill volume around a structure and the material you need to import, using whichever compaction convention your source figure came from.
- Trench Volume Calculator Calculate trench excavation, pipe bedding and backfill for a pipe run in one pass.
Rebar & Steel
Bar weights, bar counts and spacing for reinforcement.
- Rebar Weight Calculator Calculate the weight of reinforcement bars from diameter, length and quantity.
- Rebar Spacing Calculator Work out how many bars fit across a span at a given maximum spacing, and the total bar length for a one-way or two-way mat.
Masonry
Brick and block counts with the mortar to lay them.
- Brick & Block Calculator Calculate how many bricks or blocks a wall needs, including walls more than one unit thick, along with the mortar between them.
- Mortar Calculator Convert a mortar volume into cement, sand and water quantities for a given mix ratio.
Finishing
Paint, plaster, render and tiling quantities.
- Plaster Calculator Calculate plaster or render volume for a wall, and the cement and sand it needs.
- Paint Calculator Work out how much paint a wall or room needs, allowing for coats, openings and the coverage rate on the tin.
- Tile Calculator Calculate how many tiles a floor or wall needs, including grout joints and a cutting allowance.
Surveying & Geometry
Areas, slopes, gradients and the conversions between them.