ConcreteCalculatorHQ

Concrete Calculator for Slab

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.

Slab
Units
Concrete Volume1.36 yd³
Bags
62 x 80 lb
Weight
5,500 lb
Loads
1

How to use this calculator

  1. 1. Enter dimensions
    Fill in the required fields for this concrete form.
  2. 2. Click Calculate
    Review volume, bag counts, weight, and ready-mix loads.
  3. 3. Adjust if needed
    Open advanced options for waste, density, prices, and truck capacity.

Common examples

10×10 slab @ 4 in
Great for small pads and sheds.
20×20 patio @ 4 in
Common patio size; consider adding waste.

Estimating notes

  • 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.
  • 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.