Category

Concrete calculators

Plan slabs, footings, columns and masonry with confidence. Each tool turns dimensions into the materials you need to order, follows ACI 318 conventions where applicable, and switches between cubic yards, cubic metres, 60-lb / 80-lb sacks and 40-kg sacks without retyping. Concrete is unforgiving once it’s poured — getting the quantity right the first time saves money and rework.

All Concrete calculators

Material

Rebar Calculator

Estimate total length, weight and number of bars for a rebar grid.
Volumetric

Concrete Footing Calculator

Calculate concrete volume, bags and cost for strip, pad or pier footings.

What goes into a concrete take-off

A concrete take-off — the process of converting a drawing into a quantity to order — combines simple geometry with two adjustments most spreadsheets miss: waste factor and compaction. The geometry is straightforward (length × width × depth for a slab, π · r² · D for a column, summed volumes for stepped footings), but the real world adds spillage, over-excavation, and a bit of extra so the truck isn’t arriving with a half-yard short. Our calculators apply a default 10 % waste factor that you can tune.

Imperial vs metric units

In the U.S., concrete is ordered by the cubic yard (1 yd³ ≈ 0.7646 m³ ≈ 27 ft³). Internationally, it’s the cubic metre. Our tools show both, plus equivalent bag counts at the most common sizes — 60 lb (yields ≈ 0.45 ft³), 80 lb (≈ 0.60 ft³), and 40 kg (≈ 0.018 m³) — so a contractor and a DIYer working off the same plan can each see the number that matters to their supplier.

What these calculators don’t replace

For any structural slab, foundation or load-bearing element, a stamped design from a licensed engineer is required. Our calculators help you estimate, sanity-check, and bid faster — they are not a substitute for ACI 318 design checks, soil reports, or local code review.