Enter actual hole and post dimensions. The result estimates fill volume; it does not select hole diameter, embedment, or structural capacity.
01 / Formula
How this is calculated
Volume = π × (hole radius² − post radius²) × depth × hole count02 / Assumptions
What the estimate assumes
- ✓Holes and posts are modeled as round, straight cylinders.
- ✓The post is centered and extends through the entered concrete depth.
- ✓Bell bottoms, irregular excavation, and below-hole gravel are excluded.
03 / Worked example
See the math in context
Ten 12-inch-diameter holes, 30 inches deep, with 4-inch round posts require about 17.45 cubic feet before waste.
04 / Guidance
Measure real holes
Augered holes are rarely perfect cylinders. Checking diameter and depth at several points helps you choose a realistic allowance for soil variation and cave-in.
Questions
Frequently asked
Should I order exactly the calculated amount?+
Usually no. Excavation variation, form dimensions, spillage, and uneven subgrade can increase actual volume. Use the editable waste allowance and discuss minimum loads and order increments with the supplier.
How many cubic feet are in a cubic yard?+
There are exactly 27 cubic feet in one cubic yard. Divide cubic feet by 27 to convert to cubic yards.
Does this replace a structural design?+
No. These tools estimate material quantity only. A qualified professional and applicable plans, codes, site conditions, reinforcement requirements, and manufacturer instructions govern the project.
Sources