Post Hole Concrete Calculator
Fence and deck posts need concrete per hole, not a flat yardage slab. Enter how many holes, their diameter, and depth in the controls below.
Post hole concrete tally
| Item | Area | Size | Buy |
|---|---|---|---|
| Post-hole concrete | 9.0 cu ft | 15 bags | |
| Ready-mix equivalent | 0.3 cu yd | 0.5 cubic yards |
Assumptions
- 6 post holes: 10 in diameter × 30 in deep
- Waste factor: 10%
- Volume: 8.18 cu ft
- Volume with waste: 9.00 cu ft (0.33 cu yd)
- Bag yield: 0.6 cu ft per bag (check bag label)
Supplies checklist
- Gravel or crushed stone base
- Wire mesh or rebar (slabs)
- Form boards and stakes
- Concrete mixer or mixing tub
- Float and edger
Estimates only. Check the coverage figure on your product before buying.
The Handy Pages · thehandypages.com
Setting posts before you pour
Call 811 or your local utility locate service before augering. A single post hole crossing a shallow gas line turns a fence weekend into an emergency call.
Brace each post plumb in two directions while the mix cures. Slight lean at pour time becomes a permanent gate bind once the concrete hardens.
Sonotubes and bell-shaped footings change volume per hole. This calculator treats each opening as a straight cylinder using the diameter and depth you enter, which matches many pre-mixed bag projects for 4x4 posts.
About this concrete layout
Each post hole is modeled as a cylinder: radius from the diameter you enter, depth from the depth field, multiplied by how many posts you set. The worked example uses six holes at 10 inches wide and 30 inches deep with 10% waste for spillage.
Bag yield still comes from the label on the bag you buy. Ready-mix yards are shown for comparison when you are quoting a truck, not for filling individual holes with a wheelbarrow.
Use the controls below for hole count, diameter, and depth before you download.
Handy gear for mixing and finishing concrete
- Mixing tub or wheelbarrow liner for small batches (opens in new tab)
- Concrete float and finishing trowel for smooth surfaces (opens in new tab)
- Rubber or waterproof work boots for wet mix and cleanup (opens in new tab)
- Heavy rubber gloves when hand-mixing or handling wet concrete (opens in new tab)
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