Concrete Calculator
Calculate how much concrete you need for slabs, columns, walls, and footers. Get cubic yards, bags needed, and cost estimates.
Frequently Asked Questions
How many bags of concrete do I need?▼
An 80-pound bag of concrete covers about 0.6 cubic feet. For a 10x10 foot slab that's 4 inches thick, you'd need about 56 bags of 80lb concrete (or 1.24 cubic yards of ready-mix).
How thick should a concrete slab be?▼
Standard patio or walkway: 4 inches. Driveway: 5-6 inches. Garage floor: 4-6 inches. Foundation footer: 8-12 inches. Building codes may require specific thicknesses.
How much does concrete cost?▼
Ready-mix concrete costs about $125-175 per cubic yard delivered. Bagged concrete (80lb bags from Home Depot/Lowe's) costs about $5-7 per bag. For large projects (over 1 yard), ready-mix is more cost-effective.
Why does the calculator add 10% extra?▼
We add a 10% waste factor to account for spillage, uneven ground, and settling. This is standard practice — ordering exact amounts often results in running short.
How to Use Concrete Calculator
- 1Open the Concrete Calculator tool above - it loads instantly in your browser.
- 2Enter your data or upload your file. Everything is processed locally on your device - nothing is uploaded to any server.
- 3Get your results instantly. Copy, download, or share - completely free with no signup required.
Concrete Calculatoris part of BriskTool's collection of free online tools. All tools run entirely in your browser for maximum privacy and speed.