Calculate your result
Quick answer
A 10 m × 0.6 m strip at 0.25 m concrete depth contains 1.5 m³. A 5% allowance gives 1.575 m³, or 1.6 m³ if ordering in 0.1 m³ increments. These are example dimensions, not a recommended foundation design.
How it works
Use this foundation calculator for South Africa to estimate concrete for building and wall footings, pads or a specified raft. Add separate sections, quote-based costs and an optional overall rectangular set-out check.
Formula
Concrete = sum of non-overlapping section volumes + extra concrete − deductions. Apply the entered allowance, then any supplier increment. Budget = ordered concrete × quote rate + separately measured excavation × its rate + entered allowances, extra VAT and contingency.
Assumptions and common mistakes
Check units, input values and the method before relying on an estimate. Review the existing tool notes and official sources below.
Formula
Concrete = sum of non-overlapping section volumes + extra concrete − deductions. Apply the entered allowance, then any supplier increment. Budget = ordered concrete × quote rate + separately measured excavation × its rate + entered allowances, extra VAT and contingency.
How to use the foundation calculator South Africa
Start with the concrete dimensions in your project specification and measured take-off. Add each different strip, pad or slab section separately. The quantity context label identifies strip, pad or raft work but does not alter dimensions or choose a design. Calculate measured volume, then review overlap deductions, allowance and supplier rounding.
Building and brick wall foundation quantities
For a strip footing, multiply its concrete length, width and thickness in metres. Measure runs consistently and identify junctions on a sketch. At corners and T-junctions, two full rectangles can describe some of the same concrete. Stop a run at the appropriate edge or deduct the measured overlap once. Wall height or brick count alone cannot determine a suitable footing.
Square foundation calculator for pads
For a square pad, enter the same length and width. Use the count only for identical pads, and calculate different sizes as separate sections. Six illustrative 1.2 m × 1.2 m pads at 350 mm concrete depth contain 3.024 m³ before allowance. The example does not specify a safe pad size or depth.
Raft and concrete slab foundation calculator
Use a rectangular section or known area and the specified base-slab thickness. Count additional ribs, beams or thickening only for the concrete outside the base slab already included. For example only, 48 m² × 0.15 m is 7.2 m³; an additional 0.36 m³ produces 7.56 m³ before allowance. The tool does not analyse raft bearing, bending, settlement or reinforcement.
Depth of foundation: enter a specified value
The calculator does not infer safe excavation depth, concrete thickness or founding level. Ground conditions, loads, movement and the actual design affect those choices. The concrete depth field is the part filled by the concrete being counted, which can differ from the full trench depth. Have the site and specification checked before ordering.
Cost of a concrete foundation calculator
Choose Foundation budget from your quotes. Concrete is priced at the final order volume, including any entered allowance and increment. Excavation uses a separate measured volume and rate. Add whole-job reinforcement, formwork, labour, delivery, professional and other allowances only once. Select one VAT basis for every amount and add contingency only as intended.
A transparent foundation budget example
At an illustrative 1.6 m³ order and R1,500/m³, concrete costs R2,400. Separately measured 2.4 m³ excavation at R200/m³ adds R480. If other allowances total R1,120, the subtotal is R4,000. Adding an illustrative 15% VAT and then 10% contingency gives R5,060. These rates demonstrate arithmetic and are not current South African market prices.
How to square a building foundation
The optional set-out check uses the intended overall rectangle, separately from footing section dimensions. A 6 m × 8 m outline has a 10 m target diagonal. Enter either or both measured diagonals to see deviations and their difference. Check intended side lengths and opposite sides too. Equal diagonals alone do not prove an arbitrary outline is rectangular, and the tool does not set an acceptable tolerance.
Concrete, cement and block foundations
Cement is an ingredient, not the same purchasing quantity as finished concrete. Complete concrete-premix bags require the actual product yield; site mixing needs a confirmed batch recipe. A block or cinder-block wall is counted as masonry units using the separate block brick calculator. That count does not determine the footing or filled-core concrete.
What the estimate does not do
This South African quantity and quote tool does not provide a beam-on-elastic-foundation model, soil-bearing calculation, structural approval or UK-specific design. Confirm the foundation specification, required concrete, reinforcement, preparation and supplier terms for the actual site.
Last reviewed: 15 October 2026. Reviewed by the 99tools team. Editorial and corrections policy.
Quantity planning only. Confirm product suitability, concrete specification, reinforcement and site requirements for the actual project.
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Concrete guides
Frequently asked questions
How does the foundation calculator work?
It adds the concrete volumes of your measured sections, accounts for entered extras and deductions, then applies an allowance and any supplier order increment.
Can I estimate a wall or brick wall foundation?
Yes, using the concrete dimensions specified for that footing. The calculator does not choose the footing dimensions from wall height or brick quantity.
Can I use this as a raft foundation calculator?
It can estimate a specified raft base slab and additional beam or rib volumes without double counting. It does not design or analyse the raft.
Can it calculate a safe foundation depth?
No. Enter the specified concrete depth after the site and design requirements have been established. Excavation depth and concrete thickness can differ.
How do I calculate the cost of a concrete foundation?
Use the final concrete order volume and your quoted rate, then separately measured excavation and whole-job allowances. Keep VAT consistent and avoid double-counted items.
How do I square a foundation with the calculator?
Use the separate overall rectangular set-out fields to calculate √(length² + width²). Check the intended sides and both measured diagonals. No automatic pass/fail tolerance is assumed.
Is this a cement or block foundation calculator?
Finished concrete, cement ingredients and masonry blocks are different quantities. Use a declared premix yield or confirmed batch recipe for ingredients and the block tool for masonry units.
Related calculators
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Brick Wall Calculator South Africa
Calculate single or double-skin wall bricks and costs using your quotes. Check maxi or cement brick coverage and download results as an Excel-ready CSV.
Concrete Slab Calculator South Africa
Calculate slab concrete volume, premix bags or quoted costs from rectangles, triangles, circles or known area. Check sub-base volume and rectangle diagonals.
Helpful guides
How to Calculate Concrete Volume in South Africa
Calculate concrete volume by converting every dimension to metres and multiplying length × width × depth. Keep measured volume separate from allowance and.
How Much Does It Cost to Build a Brick Wall in South Africa?
Build a brick wall budget from current quotes for bricks, completed-wall labour, mortar, foundations, finishes and delivery.
Ready-Mix Concrete Order Guide South Africa
Calculate the required finished volume, confirm the specified concrete and obtain a complete South African supplier quote. A volume result alone is not a.