HomeExpertly
www.homeexpertly.comConcrete Calculator
Estimate how much concrete your project needs. Choose a slab or footing, a round column, or a round slab, enter the dimensions and how many identical pours, then add a waste allowance and a bag size. You'll get the volume in cubic feet and cubic yards, how many bags of pre-mix to buy, and the ready-mix or bagged cost — with a bags-by-size comparison, a by-waste table, a chart, and a downloadable PDF report.
US feet and inches. Volume is figured from the shape and size (slab = length × width × thickness; round = π × radius² × height/thickness), plus a waste allowance, then converted at 27 cubic feet per cubic yard. Bag yields: 80 lb ≈ 0.60 cu ft, 60 lb ≈ 0.45, 40 lb ≈ 0.30. Round up and keep a margin — running short mid-pour risks a cold joint. Ready-mix usually has a minimum load and delivery fees. Confirm quantities and mix with your supplier. An estimate, not professional advice.
1
Shape & size
Slab / footing
Round column
Round slab
ft
ft
in
×
2
Mix & waste
%
40 lb
60 lb
80 lb
3
Cost (optional)
$
$
Concrete needed
— cu yd
Enter the shape and size, then click Calculate
Cubic feet
—
with waste
Bags needed
—
80 lb bags
Ready-mix cost
—
estimated
Concrete summary
Enter the pour
We work out the volume from the shape and size, add a waste allowance, and convert it to cubic yards and bags of pre-mix.
Concrete breakdown
Shape—
Dimensions—
Number of pours—
Volume per pour—
Total volume—
Waste allowance—
Volume with waste—
Cubic yards—
Bag size—
Bags needed—
Ready-mix cost—
Bagged cost—
Result summary
Cubic yards
—
Bags needed
—
Ready-mix cost
—
Cubic feet
—
Bagged cost
—
Volume / pour
—
Bags by size
| Bag size | Yield | Bags | Bagged cost |
|---|---|---|---|
| Enter the pour to compare | |||
By waste allowance
| Waste | Volume | Cubic yards | Ready-mix cost |
|---|---|---|---|
| Enter the pour to compare | |||
Visualizations
Bags needed by bag size (highlighted = your bag)