Calculators and guides
Six complete estimators, each with its formulas, assumptions, rounding rules and sources on the page. Plus 28 reference guides covering the numbers behind them.
Calculators
Count decking boards by row rather than by area, plan the cuts, and size the joists, bearers, posts, fixings and post-hole concrete.
Produces
Board rows, not area · Board direction · Cutting plan · Frame · Fixings · Post-hole concrete
Open the decking calculator →Regional versions
Work out gravel, chippings and sub-base quantities by volume, weight, bags, bulk bags or tonnes — including the compaction allowance most calculators leave out.
Open the gravel calculator →Produces
Volume · Compaction · Weight · Purchase units
Calculate concrete volume, bag counts, ready-mix orders, sub-base and mesh for slabs, bases and pads in cubic metres or cubic yards.
Produces
Volume · Bag counts · Ready-mix · Sub-base · Reinforcement
Open the concrete slab calculator →Regional versions
Estimate topsoil for lawns, borders and raised beds in litres, cubic metres or cubic yards — with the settlement allowance that stops beds sinking.
Open the topsoil calculator →Produces
Volume · Settlement · Litres and bags · Weight
Count slabs or pavers including joint widths, then size the sub-base, bedding mortar, jointing compound and edge restraints for the whole build-up.
Produces
Unit count · Pattern and waste · Random-size packs · Bedding · Jointing
Open the patio and paving calculator →Regional versions
Count bricks or blocks from the co-ordinating size, deduct openings, and size the mortar, sand, cement and wall ties for single skin, solid and cavity walls.
Open the brick wall calculator →Produces
Co-ordinating size · Openings · Mortar · Sand and cement · Wall ties
Guides
Decking
Board counts, gaps, cutting plans and the frame beneath — for timber and composite decks.
Gravel and aggregates
Volumes, densities, depths and the compaction allowance that decides whether your sub-base order is right.
Concrete
Slab volumes, bag yields, ready-mix ordering and the thickness that suits the job.
Topsoil
Depths for lawns and beds, settlement allowances, and what a bulk bag holds.
Patios and paving
Slab counts including joints, sub-base depth, bedding mortar and jointing.
Brickwork
Brick and block coverage, standard sizes, mortar quantities and wall areas.
Planned calculators
These are on the roadmap. They are listed here rather than published as empty pages — a calculator ships when its logic, tests, regional data and methodology are complete, not before.
- Tarmac driveway calculator
- Asphalt calculator
- Fence calculator
- Shed base calculator
- Plasterboard calculator
- Drywall calculator
- Roofing calculator
- Insulation calculator
- Turf calculator
- Mulch calculator
- Retaining wall calculator
- Post-hole concrete calculator
- Stair calculator
- Stair stringer calculator
- Driveway cost estimator
- Paint calculator
- Tile calculator
- Screed calculator
- Mortar calculator
- Block calculator
- Concrete footing calculator
- Concrete column calculator
- Concrete steps calculator
- Deck stair calculator
- Skip-size calculator
- Excavated soil calculator
- Aggregate delivery calculator
- Timber cut planner
- Room renovation estimator