How to Calculate Concrete Needed To Pour a Slab

concrete patio

Whether your construction project involves pouring a concrete slab for a patio, shed floor or basement the equation is the same. With a few basic math skills you can accurately determine the amount of concrete required to pour the slab.

Things You'll Need

• paper
• pencil
• basic math skills
• tape measure

Instructions

1. 

   First you need to determine the volume of the slab you wish to pour. Like anything else it is done by multiplying the length times the width times the height. Generally concrete slabs are poured to a thickness of 4in.(0.33 foot) or 6in.(0.5 foot). For illustrative purposes we will use a slab 10ft X 10ft X 6in.(0.5ft).

   10 x 10 x 0.5= 50. That is 50 cubic feet volume.

2. 

   Concrete is sold by the cubic yard (3ftx3ftx3ft) or 27 cubic feet. Simply divide the needed volume (50) by 27 (cu ft per yard) to determine how much concrete you need to order.
   50 ¸ 27 = 1.85 cubic yards.
   It is better to have more than is needed just to be safe, so you would want to order 2 cubic yards.

3. 

   While there are many different kinds of bagged concrete available at your local home improvement store, because of their low yield they should only be used for setting posts and other small projects. For large projects have a local supplier deliver the concrete to your work site.

Resources

• How to Build a Shadow Box Fence
• PawPawFrankie's Other eHow Articles