Free Tool
Free concrete calculator
Enter your slab, footing, or column dimensions and get cubic yards, cubic feet, and bag counts, with a waste allowance built in. Order the right amount the first time. Free, no signup.
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Order it right the first time
Coming up short on a pour is the worst way to lose an afternoon. Ordering way over is money in the driveway. This calculator gets you close.
Pick the shape, enter the dimensions, and it gives you cubic yards, which is what the ready-mix plant asks for. It also shows cubic feet and bag counts for the small pours you handle yourself.
The waste allowance matters. Forms flex, subgrade is never perfect, and spillage happens. Ten percent is a common starting point. Bump it up for rough ground or a tricky pour.
For anything over about a yard, ready-mix almost always beats bags on both price and time. Under that, bags can make sense, and the counts above are rounded up so you do not run out.
Questions
How many cubic feet are in a yard of concrete?
27 cubic feet make one cubic yard. The calculator converts for you and shows both.
How much waste should I add?
Ten percent is a common allowance for a clean slab. Add more for rough subgrade, hand digging, or a pour with a lot of edges.
How many bags do I need?
A 60 lb bag yields about 0.45 cubic feet and an 80 lb bag about 0.60. The calculator rounds the counts up so you have enough.
Is this really free?
Yes. No email, no signup, and nothing you type leaves your browser.
Turn the takeoff into a priced estimate
Werx takes your quantities and turns them into a branded estimate and proposal in one step, then tracks the real cost as you pour. 14-day free trial, no credit card.
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Disclaimer: These free tools and templates are provided for general information and estimating purposes only. All results — including quantities, material and cost estimates, load, sizing, and span figures, scores, and any guidance or warnings — are rough approximations that may not fit your specific project, site conditions, local building codes, or current prices. They are not engineering, architectural, structural, legal, financial, or other professional advice, and are not a substitute for a licensed engineer, architect, contractor, or other qualified professional. Always confirm quantities, sizing, and structural, electrical, mechanical, and code requirements with a licensed professional and your local authority having jurisdiction before purchasing materials or performing any work. Werx makes no warranty as to accuracy and accepts no liability for any decision made using these tools. Use at your own risk. See our Terms of Service.