Phase 4 · Home & Construction
Concrete Calculator
Mix slabs, footings, columns, and stairs in one plan. Get cubic yards, bag counts, and cost with waste built in so you buy the right amount the first time.
Slabs, footings, columns, stairs.
80/60/50 lb with price per bag.
Works great on phones and tablets.
Mix slab, footing, column, and stair volumes. We sum everything, add waste, then convert to bags and cost.
Set dimensions in feet/inches as labeled.
Set dimensions in feet/inches as labeled.
Set dimensions in feet/inches as labeled.
How to use this calculator
Back to homeChoose slab, footing, column, or stairs and enter dimensions. Add multiple sections for complex pours.
Use 5-10% waste for small projects. Pick bag size and price per bag to see how many bags to buy and total cost.
We roll up all sections into cubic yards, add waste, and convert to bag counts with a cost estimate.
Frequently Asked Questions
Multiply length × width × thickness (in feet) for slabs, length × width × depth for footings, and πr²h for columns. Stairs can be estimated as half the volume of a rectangular block using tread and riser dimensions.
About 45 80 lb bags make one cubic yard. 60 lb bags need roughly 60 per yard, and 50 lb bags need about 80 per yard because each yields less volume.
5-10% is typical for small pours to cover spill, uneven subgrade, and bucket losses. Larger pours or rough forms may need up to 15%.
If you need more than 2 cubic yards, bagged concrete can be labor-intensive. Ready-mix trucks save time and deliver consistent batches.
No. The calculator measures concrete only. Base material is compacted separately and not counted in concrete volume.
Sidewalks commonly use a 4-inch slab. Driveways often need 4-6 inches depending on load and soil conditions.
Add each slab as its own section. The calculator sums all sections, applies waste, then converts to bags and cost.
Pick the bag size you plan to buy. If you mix sizes, use the primary bag size for the estimate and keep a few extras in another size if needed.