How much concrete do I need?
Concrete Calculator
Type the length, width, and thickness you measured. Cubic yards, a 10% extra for waste, and bag counts appear as you type. Pour Plan is a homeowner estimating guide. It is not a contractor, and it does not place a concrete order.
- No ads
- No order button
- US feet and inches
- Math you can check
Your estimate
Start with a common job
These examples fill the calculator so you can see the math, then overwrite the numbers with your tape measure.
A problem, then the page that answers it
After the number
What the calculator reports
Each tool uses US customary units: feet, inches, cubic feet, and cubic yards. Thickness is entered in inches because that is how a slab is usually specified. The calculator converts that thickness to feet, multiplies the three dimensions, and divides by 27, so the main result is in cubic yards.
A second line shows cubic feet. After a volume result you also see a 10 percent extra for waste and a typical bag count. Change those assumptions on the waste and bag pages. Other shapes — walls, curbs, rings, stairs, and footings — use the same units on their own pages. None of these pages prices labor, designs reinforcement, or reviews a building permit.
Frequently asked questions
- How much concrete do I need? Measure length and width in feet and thickness in inches. The calculator multiplies those dimensions, divides by 27, and shows cubic yards. Treat that number as a plan, not an order.
- What thickness should I enter for a patio slab? Many residential slabs land in a 3.5 to 4 inch range, and driveways are often thicker. Those are common field ranges, not a code review. Confirm the number your local code and your soil actually need.
- Does the estimate include waste? The tools report the volume of the shape you typed. Each result also shows a 10 percent extra for waste. Use the waste-factor tool when you want a different percent.
- I only know the square footage. Can the calculator still run? Yes. On the slab calculator, leave length and width blank and enter square feet plus thickness.
- How do I estimate an L-shaped patio? On the full slab calculator, add the first rectangle, change the numbers, and add the second. Do not count the corner twice. How to split an L.
- How do I convert cubic feet to cubic yards? Divide cubic feet by 27. The converter does that on its own. The slab calculator does it after it multiplies length, width, and thickness in feet.
- Can I use this number to order a truck? No. Treat the result as a planning figure. Suppliers round yards, and a dispatcher will still ask about access, slump, and timing. The calculator does not place an order.
- Is Pour Plan a Kansas City concrete company? No. Pour Plan is an independent estimating guide. It does not run a crew, publish job photos, or take placement calls. Climate notes about the Midwest are general field notes, not a claim of local service.