About this tool
Updated .
A tool for planning your concrete order
This calculator estimates geometric volume, bag quantities and optional material costs. It supports slabs, walls, round columns, hollow cylinders, solid stairs and ramps, with multiple areas and mixed measurement units.
Developed and maintained under the pen name Evan Brooks. Based in New York, United States.
The formulas and assumptions are visible so you can check an estimate before using it. It is a planning tool, not a structural engineering service.
Sources and calculation method
Unit conversions follow NIST conversion factors. Preset bag yields come from the QUIKRETE Concrete Mix No.1101 data sheet. Other products need their own yield; bag weight alone is insufficient.
Read the formulas, worked example and original sources. Product references identify calculation inputs and do not imply endorsement or affiliation.
Corrections
If a result looks wrong, compare the dimensions, units, reserve, product yield and rounding first. See how to report a reproducible issue.