How to Measure for Concrete

For a slab or footing, measure length, width, and thickness — concrete volume is length × width × thickness (converted to feet) ÷ 27 for cubic yards. Standard slab thickness is 4 inches for patios and walkways, 5–6 inches for driveways.

For round footings like fence posts, measure the hole diameter and depth instead — the calculator uses cylinder volume (π × radius² × height) and lets you multiply by the number of identical holes.

Use the Concrete Calculator for footings and columns, or the Concrete Slab Calculator for a slab-focused workflow with bag counts included.

Concrete reaches roughly 70% of its final strength in the first week and keeps curing for about a month. Plan the pour around the weather forecast — concrete poured in freezing temperatures without protection can fail to cure properly at all, not just cure more slowly.