Concrete Footing Calculator
Estimate the concrete for footings, strip foundations and grade beams. Enter length, width and depth — and set quantity if you have several identical runs.
Continuous strip footings and grade beams.
How to calculate concrete for a footing
The formula
A strip footing is a long rectangular prism: length × width × depth. For multiple identical footings, set the quantity. Round pier holes use the column shape instead.
- Strip footing = length × width × depth.
- Pier / pad footing = use quantity for repeated units.
- Footings are usually poured at a lower strength than slabs.
Worked example
A continuous footing 60 ft long, 18 in wide, 12 in deep:
- Convert: 18 in = 1.5 ft, 12 in = 1 ft.
- Volume = 60 × 1.5 × 1 = 90 ft³ = 3.33 yd³.
- Add 10% waste → about 3.7 yd³ (2.8 m³).
Order about 3.7 cubic yards (2.8 m³) for this footing.
Sizing, thickness & waste
Footing size basics
- Footing width is typically 2–3× the wall thickness it carries.
- Minimum depth is usually 12 in (300 mm), below the frost line in cold climates.
- Always follow your local code and engineer's drawings.
Foundations often suit on-site batching
Foundation pours are frequently large, continuous and on sites without easy ready-mix access. A foundation-light compact or mobile plant lets you batch fresh concrete exactly when each section is ready.
What produces this much concrete?
Foundation work pairs well with mobile production. For your volume:
Small pour — mix on site
Under ~0.5 m³ (≈0.65 yd³) you can mix on site from bags. A portable mixer saves time over hand-mixing once you pass a few bags.
Medium pour — small mixer or ready-mix
From ~0.5–2 m³, a small or self-loading mixer keeps you independent of delivery schedules; otherwise order ready-mix.
Large pour — self-loading mixer or delivery
At 2–10 m³, compare ready-mix delivery against a self-loading mixer or mixer truck if you pour regularly.
On-site batching becomes economical
Above ~10 m³, repeated or remote pours usually cost less with on-site batching than per-load delivery. A mobile or compact plant sets up fast.
Continuous production — dedicated plant
Beyond ~50 m³ per job, a stationary or ready-mix plant delivers the throughput and consistency large projects need.
Frequently asked questions
How do you calculate concrete footings?
Multiply the footing's length × width × depth for the volume of one run, then multiply by the number of identical footings. Enter the dimensions above to get cubic yards, cubic metres, bags and cost.
How do you calculate concrete for a foundation?
Break the foundation into simple shapes — strip footings (length × width × depth) and any pad or column footings (set the quantity) — add the volumes, then add 5–10% waste. The calculator handles both strip and round footing shapes.
How deep and wide should a concrete footing be?
Footings are typically at least 12 inches (300 mm) deep, below the local frost line, and 2–3× as wide as the wall they support. Exact sizing depends on load and soil — follow your engineer's design and local building code.
How many cubic yards are needed for footings?
Divide the footing volume in cubic feet by 27. A 60 ft run at 18 in wide × 12 in deep is 90 ft³ = 3.3 cubic yards before waste.
How much concrete is needed for a column footing?
For a square pad, use length × width × depth; for a round pier, use π × (diameter ÷ 2)² × depth. Set the quantity to the number of identical footings.
What equipment is suitable for foundation concrete?
Foundation pours are often large, continuous and on sites without easy ready-mix access — a foundation-light mobile or compact batching plant lets you batch fresh concrete on demand. See the equipment guide above for your volume.
How much extra concrete should I order for waste?
Add 5–10% to your calculated volume to cover spillage, uneven subgrade, and over-excavation. For small or irregular pours, 10% is safer because running short mid-pour creates a cold joint.