Concrete · Free Tool

Concrete volume calculator.

Cubic yards, 60-lb and 80-lb bag count, plus a recommendation on whether you should order ready-mix or just buy bags. Slab, strip footing, square column, or round Sonotube — all in one tool.

Inputs

4″ residential walking · 5-6″ driveway · 8″ heavy load.

10% ready-mix · 15% bagged work.

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Cubic yards
2.72
yd³

20 ft × 10 ft × 4" · 66.67 ft³ raw · 10% waste added.

80 lb bags
123
bags

Probably more efficient to order ready-mix.

60 lb bags
163
bags

If 80 lb is sold out or too heavy.

Rebar (#4 / 1/2″)
16
× 20 ft sticks

Grid at 18″ o.c. with 10% overlap.

Ready-mix order
2.72
yd³

Most plants have a 0.5-1.0 yd minimum + short-load fee.

Field notes. Order ready-mix when you're over ~0.75 yd³ — bagged becomes backbreaking and inconsistent. Frost line in southern Ontario is 48″; in the GTA most decks pier to 4 ft min. Add fiber mesh reinforcement to ready-mix for slabs < 6″ thick. Pour during the cool of the morning in summer; never below 5°C without a hot mix and blankets.
Material list — ready to order

Take this to the yard.

Copy/paste into an email, screenshot it for your supplier, or tap a partner below to send it straight to their order desk.

Ready-mix concrete
2.72yd³
80 lb bags (alternative)
123bags
Rebar #4 × 20 ft
16sticks
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