How to use it
- Enter the patio length in feet.
- Enter the width in feet.
- Enter the slab thickness in inches.
- Get your concrete volume and bag count instantly.
This calculator turns three simple measurements — length, width, and thickness — into the exact concrete volume you need for your patio. It shows the result in cubic yards, cubic feet, and the number of standard 80-lb bags, so you can order with confidence. That number matters because concrete is expensive to over-order and a pain to under-order. If you're using ready-mix, you'll want cubic yards. If you're mixing bags yourself, you'll want the bag count. The cubic feet figure gives you a direct reference for both. Just enter your dimensions, and the calculator does the rest — no guesswork, no math errors, no last-minute trips to the hardware store. Whether you're pouring a small walkway or a large backyard patio, knowing exactly what to buy saves time, money, and wasted material.
Pro tips
- Add 5–10% for waste, spillage, or slight depth variations before ordering.
- Always round up your bag count to the next whole bag — partial bags aren't practical.
- For large patios, compare bag totals against ready-mix cubic yards; bulk delivery is often cheaper.
- Measure in feet and inches carefully — a small error in thickness can change your bag count significantly.
Real-life examples
- Planning a 10x10 backyard patio slab and need to know how many bags to buy.
- Estimating concrete for a 12-foot round or rectangular patio extension.
- Comparing ready-mix delivery vs. mixing 80-lb bags for a small walkway.
Case study
Mark planned a 12x15 patio at 4 inches thick. Instead of guessing, he entered his numbers into the calculator. It showed 2.22 cubic yards — about 100 bags. He added 10% waste and ordered 110 bags. The pour went smoothly with no extra trips, and he returned two unopened bags.