Concrete volume calculator
Choose a shape, enter dimensions in feet and inches, then get cubic feet, cubic yards with waste, and bag counts for common premix sizes.
Last updated:
Enter measurements in:
Long side of the slab
Short side of the slab
Slab thickness
Frequently asked questions
- How do I convert cubic feet to cubic yards?
- Divide cubic feet by 27 to get cubic yards. Ready-mix concrete is ordered by the cubic yard, which is why the calculator shows yards after applying your dimensions.
- Why is 10% waste added to cubic yards?
- Extra volume covers spillage, uneven subgrade, and small measuring errors. It is a practical buffer for homeowners so you are less likely to come up short mid-pour.
- When should I use bags instead of a ready-mix truck?
- Bags work well for small pours you can mix in a wheelbarrow—post holes, patches, and tiny slabs. Around one cubic yard or more, or any pour that must finish quickly, usually favors a ready-mix truck.
- What is the difference between slab, footing, and column shapes?
- All three use length × width × depth, but the labels help you measure correctly: a slab is a flat pad, a footing is a strip or pad below a wall or post, and a column is a vertical pour with height as depth.
- How accurate are the bag counts?
- Bag totals use common yield values for 40, 60, and 80 pound premix bags plus the same 10% waste as cubic yards. Check the yield printed on the bags you buy, since brands can differ slightly.
How to use this concrete calculator
Pick slab, footing, or column, then enter length and width in decimal feet or feet plus inches. Depth stays in inches—the way most home pours are sketched.
You get cubic feet, cubic yards with ten percent waste, and bag counts for forty-, sixty-, and eighty-pound premix. Compare yards to a ready-mix quote when the job is larger than a wheelbarrow pour.
Related guide
Turn length, width, and thickness into cubic yards and bag counts—whether you are pouring a slab, footing, or column.
Read: How to Calculate Concrete for Any Project →