Concrete Pier Calculator

Calculate concrete volume for piers, drilled shafts, and caissons with optional belled base.

Decision Guide

Pier and drilled-shaft buying decision

Piers become expensive when the geometry is wrong, not just when the volume is large. The key decision is whether the shaft, bell, and pier count still make this a simple bag job.

Best default

Bagged mix is still realistic

Budget check

Use total waste-adjusted volume across all piers, not just one shaft, when you price the pour.

Logistics

Belled bases and multiple piers can turn a small-looking job into a much larger material run.

Before you order

  • Bell geometry changes volume faster than most people expect.
  • Total pier count matters more than one sample pier.
  • Irregular holes can justify extra margin beyond the clean math.

Next steps

  • Confirm whether the pier includes a belled base.
  • Price total waste-adjusted volume across all piers together.
  • If the count grows, compare bags against one coordinated truck order.

Common mistakes

  • Ignoring bell volume on belled piers.
  • Pricing one pier and forgetting the whole run.
  • Buying the exact shaft math with no field margin.

Use this as a planning guide. Engineering requirements and local soil conditions still control the final pier design.

1. Enter Pier Dimensions

Shaft diameter, depth, and optional bell.

Common: 10", 12", 14", 16" for decks

2. Results

Your pier concrete calculation.

Enter pier dimensions

Fill in the diameter and depth to calculate concrete volume.

About Concrete Piers

Concrete piers are deep foundation elements that transfer structural loads to competent soil or rock below. They are used for decks, porches, foundation repair, and new construction where shallow foundations are inadequate.

Types of Concrete Piers

  • Drilled Shaft: Cylindrical hole filled with concrete, most common type
  • Belled Pier: Wider base (bell) at the bottom for increased bearing capacity
  • Micropile: Small diameter (under 12") for tight spaces and retrofit work

When to Use Concrete Piers

  • Deck Supports: 10-12" diameter, 3-5 feet deep
  • Foundation Repair: 12-16" diameter, 10-20+ feet deep
  • New Construction: 16-24" diameter, engineered depth
  • Porch Columns: 12-14" diameter, below frost line

Standard Pier Sizes

DiameterTypical DepthApplication
8-10"3-4 ftFence posts, small structures
10-12"4-5 ftResidential decks
12-16"5-10 ftPorches, additions
16-24"10-20+ ftFoundation repair, new construction

Frequently Asked Questions

How much concrete do I need for a pier?
For a 12-inch diameter pier, 5 feet deep: Volume = π × (6/12)² × 5 = 3.93 cubic feet = 0.15 cubic yards per pier. Add 10% for waste.
What is a belled pier?
A belled pier has a wider base at the bottom that spreads the load over more soil area. The bell is typically 2-3 times the shaft diameter. This increases bearing capacity without increasing shaft size.
How deep should concrete piers be?
Deck piers should extend below the frost line (36-48 inches in most areas). Foundation repair piers typically go 10-20 feet deep. Always check local building codes for minimum depth requirements.
What diameter pier for a deck?
Most residential decks use 10-12 inch diameter piers. For heavy loads or two-story decks, use 14-16 inch diameter piers. Consult an engineer for spans over 12 feet.