Calculators
Free building-materials calculators from Build Journal: concrete, aggregate, mortar, bricks, topsoil and more.
All building calculators
MOT Type 1 Calculator
Enter your area and the compacted depth for the tonnes and bulk bags of Type 1 to order, with the compaction allowance built in.
Concrete Block Calculator
Give it a wall size and take off the openings for the number of standard 440 x 215mm blocks, wastage added.
Concrete Calculator UK
Enter the slab size and pick a mix for the cement, sharp sand and ballast, plus the total m3 for ordering ready-mix.
Sand and Cement Calculator
For paving beds, patios, single-skin brickwork and screed: sand in tonnes and bulk bags, cement in 25kg bags.
Aggregate Calculator
Pick your material, enter the area and depth, and get the tonnes and bulk bags. Covers sub base, gravel and sand.
Mortar Calculator UK
Work by wall area or by brick and block count, with a 10% wastage allowance and a patio mortar mode.
Floor Joist Span Calculator (C24 & C16)
Pick C24 or C16, a joist size and a spacing for the indicative maximum clear span and the joist count for the room.
Topsoil Calculator
Enter the area and how deep you want it for the volume in m3, the weight in tonnes and the bulk bags to order.
Ballast Calculator
For a shed base, footings or a small slab: ballast in tonnes and bulk bags, cement in 25kg bags.
Gravel Calculator UK
Enter an area or a length and width, pick a depth, and get 20mm gravel in tonnes, bulk bags and 25kg bags.
Brick Calculator UK
Wall size minus the openings gives your brick count, plus the sand and cement to bed them.