Sources & calculation accuracy

We show the calculation assumptions so you can check every estimate. These are planning tools, not construction design software.

Concrete bag yield reference

Built-in presets use the published yield figures for QUIKRETE Concrete Mix No. 1101: 40 lb ≈ 0.30 ft³; 50 lb ≈ 0.375 ft³; 60 lb ≈ 0.45 ft³; 80 lb ≈ 0.60 ft³; 90 lb ≈ 0.675 ft³. Use Custom yield if your product differs.

QUIKRETE official concrete mix data sheet (PDF) ↗

Unit conversion

One yard equals 3 feet, so one cubic yard equals 3 × 3 × 3 = 27 cubic feet. A US short ton is 2,000 pounds. A material's volume-to-weight conversion requires its actual bulk density.

Density and moisture

Gravel and soil change in weight with stone type, grading, moisture and compaction. We do not assign a universal density to any material. The initially shown 1.4 short tons per cubic yard is an editable illustration only, not a supplier-verified value.

Testing scope

We test numerical conversion formulas, percent allowances, bag rounding and invalid inputs. User measurements, supplier costs, soil settling, structural loads and exact density cannot be independently verified by these tools.

Responsible use

Always check local construction codes and professional design requirements for slabs, foundations, drainage and load-bearing uses. Confirm your final order with the manufacturer or supplier.