Concrete volumes
Strip footing volume
- where
- concrete volume (m³)
- total centreline length of footings (m)
- footing width (mm)
- footing thickness (mm)
Explain this equation
Works out the concrete in strip footings under walls.
Measure the footings along their centreline so corners are counted once. Width and thickness are in millimetres, so each is divided by 1000 to convert to metres before multiplying by the length.
Volume of a long rectangular strip.
Sense check: 24 m of 600 × 225 mm footing is about 3.2 m³.
Watch out: trenches are often dug wider than drawn, especially in loose ground. Measure what has been dug before ordering.
Works out the concrete in a traditional strip footing of constant width and thickness, given the total run of footing.
Enter your values to see the result.
Good to know
Measure the run along the centreline of the footing. Measuring round the outside of a building counts each corner twice; the centreline gives the right volume for a constant-width strip. Width and thickness come from the engineer’s design or the Building Regulations Approved Document A guidance for the ground and wall loads.
Common mistake
Adding the outside perimeter of every wall, which double counts each corner by width × width × depth.
Limits
Constant width and thickness. Steps in the footing, piers and wider sections should be added separately. Use the trench fill calculator when the trench is filled close to ground level.
Sources
- Geometry: prism volume = plan area × depth; cylinder volume = π d²/4 × h
Results are calculations from the published methods and figures shown, and depend on the data you enter. Follow BS 8500, BS EN 206, BS EN 752, Building Regulations Part H, manufacturers’ data and your engineer’s design. Structural concrete and foundations need a competent designer.