Enter the diameter & depth in inches and the number of post holes. Click on 'Calculate' to determine the amount of concrete needed. This figures round holes only.
Cubic yards is exact with no excess. The estimate of number of bags of pre-mixed cement is rough because it depends on how wet you mix it. It also depends on how uniform you dig your holes. In the case of bagged mix, order a little less and buy more if needed. When ordering cement by the truck, order plenty and don't worry about the waste. It costs more to have the truck return for small loads.