Concrete post calculator

Bag counts for setting a post, computed from the hole's volume minus the space the post itself takes up, divided by the manufacturer's published yield for your exact product. Manufacturer worked examples shown alongside so you can see how our math compares. Sources on the methodology page.

Planning estimates from manufacturer-published yields — round up and keep a spare bag. Hole depth requirements are set by frost depth and local code, not by any calculator. Call 811 before you dig. More context in our bags-per-post guide and fence calculator.