Concrete guides

The thinking behind the calculators. Each guide answers one question, shows the math, and links to the tool that does it for you.

How to calculate concrete

The formula for slabs, round holes, footings and steps, with worked examples and the mistakes that catch people out.

Answers how to figure concrete by hand.
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How many bags of concrete in a yard

What each bag size yields, where the figures come from, and coverage tables for 2, 4 and 6 inch pours.

Answers bag counts and yields.
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Bags vs ready-mix

When a truck is worth it, what minimum loads and short-load fees mean, and how to compare the two at your prices.

Answers how to buy concrete.
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How much extra concrete to order

Why every calculator adds 10%, what it covers, and when to order more or less.

Answers the waste allowance.
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