Calculate concrete volume for identical round foundation piles or reverse-solve pile count or diameter in metric or imperial length and volume units.

Optional settings

Pile Quantity Formula

The pile quantity calculator estimates nominal volume for identical solid cylindrical piles, the minimum whole pile count to reach a target volume, or the nominal diameter for a target volume. Enter diameter and length; these are geometric calculations, not structural or geotechnical design checks.

PQ = π r² h n

Calculate one cylinder volume and multiply by the number of identical piles. The radius in this equation is half the diameter entered in the calculator: r = d / 2. Thus one pile has volume π × d² × h / 4.

Variable Meaning Typical Units
PQ Total nominal pile volume m³, ft³, yd³
r Radius: half the entered diameter m, ft
h Length of one pile m, ft
n Whole number of identical piles count

Useful Rearrangements

Diameter mode solves the positive nominal diameter below. The height identity is valid algebra, but height is an input rather than a separate solve mode. For count mode, the count equation gives an exact quotient; round it upward to the minimum whole count whose nominal volume reaches the target. The resulting schedule may exceed the target volume.

d = √((4PQ) / (π h n))
h = (PQ) / (π r² n)
n = (PQ) / (π r² h)

The calculator accepts diameter directly. The radius identity below explains the equivalent radius-based formulas; do not halve the diameter before entering it.

r = (d) / (2)

How to Calculate Pile Quantity

  1. In total-volume mode, enter the diameter of one pile.
  2. Enter pile length and choose its unit; diameter and length may each use meters or feet.
  3. Enter a positive whole number of identical piles.
  4. Volume per pile is pi times diameter squared times length, divided by four. Multiply by pile count.
  5. Read the total in the selected volume unit; the calculator converts the length and volume units.

Volume depends on diameter squared: doubling diameter quadruples nominal volume when length and pile count stay fixed.

Example

Suppose each pile has a radius of 0.25 m, a height of 10 m, and there are 24 identical piles. Enter diameter 0.5 m, length 10 m and count 24 in total-volume mode.

PQ = π (0.25)² (10)(24)
PQ ≈ 47.12 m³

This means the total cylindrical volume for the pile group is approximately 47.12 cubic meters.

Unit Notes

  • Choose meters or feet separately for pile diameter and length.
  • Choose cubic meters, cubic feet or cubic yards independently for the target and result volume.
  • Convert dimensions given in inches before entry; inches and cubic inches are not calculator selections.
  • Match each value to its own selected unit. The calculator converts dimensions before applying the formulas. Conversions use exact factors, including 1 ft = 0.3048 m (NIST).

What This Calculator Assumes

  • Each pile is modeled as a perfect cylinder.
  • All piles in the calculation have the same diameter and length.
  • Count is a whole-number multiplier; count mode finds the minimum number reaching a target, not the maximum fitting within a fixed concrete budget.

If your project includes multiple pile sizes, varying embedment depths, tapered piles, or non-cylindrical sections, calculate each group separately and add the totals together.

Common Input Mistakes

  • Entering radius where the calculator requires diameter.
  • Forgetting that volume grows with the square of diameter at fixed length and count.
  • Using inconsistent units between inputs.
  • Using one average value for piles that actually have different lengths or diameters.
  • Assuming this result is weight or structural capacity; it is volume only.

Practical Interpretation

The result is theoretical geometric volume, not a concrete order or a safe foundation design. FHWA distinguishes theoretical and actual drilled-shaft concrete volumes. Construction overbreak, reinforcement displacement, cut-off, waste and project specifications require separate assessment; no allowance is automatically added here.