Concrete for fence posts should be based on the annular volume around each post, not on hole volume alone. Calculate the hole cylinder, subtract the portion occupied by the post when appropriate, multiply by the number of holes, then divide by the selected concrete mix yield.
For each fence post, calculate the cylindrical hole volume, subtract embedded post displacement when appropriate, multiply by the matching post count, then divide by the selected concrete mix yield and round up to whole bags.
Published: September 20, 2026
Last reviewed: September 20, 2026
Published by BuildYard. The guide reflects BuildYard's calculation methodology and editorial standards and does not replace project-specific professional advice.
Use actual hole diameter and concrete-filled depth for each post type.
Corner, gate, terminal, and line posts can require different holes, so estimate them separately when dimensions differ.
A post occupying the concrete zone reduces the concrete volume.
Use the actual post width or diameter and only the embedded length that overlaps the concrete.
Group identical holes and calculate each group once.
Do not let gate hardware or brace posts disappear inside a generic waste percentage.
Convert the adjusted cubic-foot requirement with the exact yield of the selected concrete product.
Fast-setting products can have different package sizes and instructions from standard concrete mix.
Round up to whole bags after all hole groups and allowances are combined.
Hole depth, frost requirements, soil conditions, and structural loads remain project-specific.
Fence Calculator estimates posts, panels, rails, and pickets for general straight-run fence takeoffs.
Open calculator →ConcreteConcrete Calculator estimates ready-mix concrete, bag mix, weight, and truck loads for general slabs, pads, walls, and rectangular pours.
Open calculator →BuildYard geometry example before post displacement: each 12 in diameter × 30 in deep cylinder is about 1.96 cu ft.
| Step | Result |
|---|---|
| Volume per hole | 1.96 cu ft |
| Ten holes | 19.63 cu ft |
| Post displacement | Subtract actual embedded post volume |
| Bag conversion | Use selected concrete product yield after subtraction |
External references open in a new tab. BuildYard references stay on this site. Each link points to the specific technical document, article, product data, or standard page used for the related statement.
Calculate concrete volume for round post holes while subtracting square or round post displacement and converting to bags.
Read guide →ConcreteCalculate concrete for post holes by cylinder volume, post displacement, bag yield, hole count, and waste.
Read guide →FencingEstimate fence posts and panels by splitting a layout into straight runs, applying spacing, and accounting separately for corners and gates.
Read guide →Current manufacturer data, supplier specifications, drawings, field measurements, applicable codes, permit requirements, and qualified professional guidance can take priority over a general-purpose planning estimate.