Enter the length, width, and thickness of your slab, footing, or patio. The calculator instantly gives you the total volume in cubic yards and cubic feet, the number of pre-mixed bags you'll need (60 lb or 80 lb), and a waste-adjusted total so you don't run short on pour day. It also estimates how many ready-mix truck loads you'd need if you go the delivery route.
No pour is perfectly flat. Subgrade settles, forms bow, and spills happen. The industry standard is to add 5–10% for waste. Our calculator includes a 10% waste factor by default. If your subgrade is particularly uneven or you're working with complex forms, consider going up to 15%.
For small projects under 1–2 cubic yards (like a small patio or fence footings), mixing bags on-site is usually the way to go. You control the timing and avoid minimum delivery charges. For larger pours — driveways, large slabs, or anything over 2 yards — ready-mix is faster and often cheaper. Most trucks carry 8–10 cubic yards and many suppliers have a 1-yard minimum.
A 10×10 slab at 4 inches thick is about 1.23 cubic yards. That's roughly 56 eighty-pound bags. With 10% waste, order 62 bags.
For projects under 1–2 cubic yards, bags are usually more practical. For larger pours, a ready-mix truck is faster and often cheaper per yard. Most trucks carry 8–10 cubic yards.
Patios and walkways: 4 inches. Driveways: 4–6 inches. Footings: 8–12 inches. Check local building codes for your area.
Always add 5–10% for waste, spillage, and uneven subgrade. For complex forms or uneven ground, add up to 15%.