Concrete quantity takeoff: measuring volume the right way

By the Give Me The Cost estimating team · Methods reviewed by a senior GTA estimator (25+ years in the field) · Updated July 2026

A concrete takeoff is a volume measurement in cubic metres (m³). You break the structure into elements — slabs, walls, footings, columns, piers — measure each as length × width × thickness, and total them by mix strength. The two things that move the number most: reading each level's real slab thickness, and not double-counting where a wall meets a footing.

Concrete is measured by volume

Every concrete line comes down to length × width × thickness, summed across every element and grouped by concrete strength (25 MPa, 30 MPa, 35 MPa) because each mix is priced and placed differently. The structural drawings and concrete notes give you the dimensions and the strengths.

The elements to measure

Slabs — slab-on-grade and every suspended floor: plan area × thickness. Read each level's thickness; they're rarely all the same.
Foundation walls — length × height × thickness around the perimeter and party walls.
Footings — strip footings under walls and pad footings under columns.
Columns & piers — cross-section × height × count.
Beams & grade beams — width × depth × length.

The mistakes that throw the number off

One thickness for every floor. A transfer slab or podium can be double a typical floor — a flat assumption can be off by hundreds of m³.
Double-counting overlaps. Where a wall sits on a footing, or a slab runs into a wall, decide once which element owns the shared volume.
Ignoring mix strength. Total by MPa — a raft at 30 and columns at 35 are different lines.
Forgetting waste. Placed concrete carries a small over-order allowance for spillage and over-excavation.

Concrete carries rebar and formwork with it

The concrete geometry you measure here is also what drives two other takeoffs: the rebar that reinforces it and the formwork that shapes it. Getting the concrete elements right once feeds all three.

Doing it faster

Give Me The Cost reads the structural set, measures every concrete element by level and strength, and returns volume in m³ — and it derives the rebar and formwork off the same geometry. On the confidence read it tells you which levels' thicknesses were measured versus assumed, so you know exactly what to spot-check. For today's Ontario concrete supply prices, see our quarterly price check.

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Frequently asked questions

How do you calculate concrete volume?
Break the structure into elements (slabs, walls, footings, columns), measure each as length × width × thickness, and total in cubic metres by concrete strength.

Why group concrete by MPa strength?
Different mixes (25, 30, 35 MPa) are priced and placed separately, so a takeoff totals each strength on its own line rather than lumping all concrete together.

What's the biggest concrete takeoff mistake?
Using one slab thickness for every floor. Transfer and podium slabs can be twice a typical floor, so a flat assumption can miss hundreds of cubic metres.

Does a concrete takeoff include rebar?
No — concrete (volume, m³) and rebar (weight, tonnes) are separate line items, though both are derived from the same structural geometry.