How to use it
- Enter the pier diameter in inches.
- Enter the pier height or depth in feet.
- Enter the number of identical piers.
- Click Calculate to see cubic yards, cubic feet, and 80-lb bags.
Concrete piers support decks, posts, and foundations. Getting the volume wrong means either running out mid-pour or wasting money on extra bags. This calculator takes the guesswork out of estimating. Enter the diameter, depth, and number of piers, and it instantly converts to cubic yards, cubic feet, and the exact number of 80-lb bags required.
Why does this matter? Concrete is sold in bags and ordered by the yard. The calculator uses the standard yield of 0.6 cubic feet per 80-lb bag, so your bag count matches your yardage. Read the results as: cubic yards for ordering ready-mix, cubic feet for estimating volume, and 80-lb bags for buying at the store. For a single pier, simply enter quantity as 1. For multiple identical piers, multiply by quantity to get the total. This saves time, reduces waste, and keeps your project on schedule.
Pro tips
- Add 10% to your bag count to cover spillage, uneven excavation, or slight mix errors.
- Round up to the nearest full bag. You can't buy a fraction of a bag, and a partial batch can weaken the pier.
- For large jobs, compare bag vs ready-mix. If you need more than 1 cubic yard, ready-mix may be cheaper and faster.
- Don't mix units—always use inches for diameter and feet for depth to avoid a 12x error.
- Common mistake: forgetting the quantity field. Double-check that it reflects the total number of piers you're pouring.
Real-life examples
- Setting deck support piers on a new backyard patio.
- Pouring concrete piers for a raised shed or storage building.
- Replacing rotted wooden posts with concrete footings along a fence line.
Case study
Before, Dana always ordered extra bags 'just in case' and ended up with waste. After using the calculator, she knew exactly how many 80-lb bags to buy for her six piers — no guessing, no leftover concrete, and no mid-pour runs to the store.