Concrete Slab Calculator
Calculate the volume and weight of concrete needed for a slab, whether it's a patio, driveway, garage floor, or shed pad. Enter your length, width, and thickness to get results in cubic yards, bags, and ready-mix truckloads. Ordering slightly more than the estimate helps avoid running short on pour day.
Form: Slab
Units:
Examples:
Examples
- 10×10 slab @ 4 in: Great for small pads and sheds.
- 20×20 patio @ 4 in: Common patio size; consider adding waste.
Estimating tips
- Add 5–10% waste for spillage and uneven subgrade.
- Double-check thickness (4 in is common for residential slabs; thicker for heavy loads).
- Measure in multiple spots and use the largest dimensions to avoid coming up short.
- If ordering ready-mix, confirm minimum loads and short-load fees with your supplier.
- Round up bags and keep an extra bag or two for small over-excavations.
Other forms
Assumptions
- Bag yields and density vary by product; verify values on your bag or supplier spec sheet.
- Cost estimates exclude delivery fees, taxes, and minimum loads.