### Calculating the amount of concrete you require for a square or rectangular slab can be confusing.

### Download a free automatic concrete calculator (you must have Microsoft Excel)

### To Download Your Free Concrete Calculator - right click - save as

### Notes:

- Pre-mix concrete comes in bags that are 60 lbs. and 80 lbs.
- A 60 lb. bag provides 0.45 cubic feet of cured concrete.
- A 80 lb. bag provides 0.6 cubic feet of cured concrete.
- If you have concrete delivered it is sold by the yard (which is a cubic yard = 27 cubic feet).

### Following are the formulas to calculate how much concrete you will require for a square or rectangular shaped pour:

#### L (feet) x W (feet) x T (inches) ÷ 12 = cubic feet of concrete (CF)

#### Number of bags of concrete needed:

#### CF ÷ 0.45 = number of 60 lb. bags

#### CF ÷ 0.6 = number of 80 lb. bags

#### Number of cubic yards of concrete needed:

#### CF ÷ 27 = cubic yards

#### L = Length in feet

#### W = Width in feet

#### T = Thickness in inches

#### CF = Cubic feet of concrete

### Example:

A patio 10' long by 8' wide - 6″ thick

10 x 8 x 6 ÷ 12 = 40 cubic feet of concrete

10 x 8 x 6 ÷ 12 = 40 cubic feet of concrete

40 ÷ 0.6 = 67 (66.7) 80 lb. bags of concrete

40 ÷ 27 = 1.5 cubic yards of concrete