Concrete Pier Hole Calculator

Instantly calculate concrete needed for pier holes—cubic yards, 80‑lb bags, and cubic feet—free and no sign‑up.

  • Free
  • No sign-up
  • Instant results

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How to use it

  1. Enter the hole diameter in inches.
  2. Enter the depth in feet.
  3. Enter how many holes you need.
  4. Read the three results instantly.

This Concrete Pier Hole Calculator converts your hole dimensions into the exact amount of concrete you’ll need. By entering the diameter, depth, and quantity, the tool computes the total volume in cubic feet, then translates that into cubic yards for ordering and the number of 80‑lb bags (each bag yields ~0.6 ft³). Knowing these numbers helps you budget accurately, avoid under‑ordering that stalls projects, and prevent excess waste. The results are displayed side‑by‑side so you can compare the three units at a glance and order the right amount the first time. No manual math, no guesswork—just clear, actionable data for any pier‑hole job.

Pro tips

  • Add a 5‑10% waste allowance to cover spillage and uneven sub‑grade.
  • Round up bag counts to the next whole bag; you can’t buy a fraction of a bag.
  • Order bags in bulk when possible to reduce delivery fees.
  • Double‑check that diameter is measured inside the form, not the outer edge.

Real-life examples

  • A homeowner adding a new deck needs to know how much concrete to fill four 12‑in. piers 2 ft deep.
  • A contractor estimating material for a fence foundation with 20 10‑in. holes 3 ft deep.
  • A landscape designer sizing concrete footings for a garden pergola with three 14‑in. holes 1.5 ft deep.

Case study

Jake was unsure how many bags to buy for his 6‑hole deck foundation. After entering 12 in. diameter, 2 ft depth and 6 holes, the calculator showed 0.23 yd³ and 11 bags, letting him order precisely and finish on schedule.

Frequently asked questions

How do I convert the calculator’s cubic feet result to cubic yards?
Divide the cubic feet by 27 (1 yd³ = 27 ft³).
What if my hole is deeper than the depth I entered?
Enter the actual depth; the calculator will adjust the volume accordingly.
Do I need to account for the space taken by rebar?
Add a small waste factor (5‑10%) to cover rebar and any voids.
Can I use the result to order ready‑mix concrete?
Yes—convert the cubic yards to the ready‑mix volume your supplier uses.
Why does the bag count sometimes seem high?
Each 80‑lb bag only yields about 0.6 ft³, so many small holes can require many bags; always round up.