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Construction & DIYGenerated accuracy model review: 2026-05-06
Concrete Calculator accuracy and testing
This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.
Formula source
- Vol(ft³) = L*W*(D/12). Yards = Vol/27. Bags = Vol * 133lb/ft³ / BagSize.
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Length: 10 ft
- Width: 10 ft
- Thickness: 4 in
- Waste Factor: 5%
- Premix Bag Size: 80 lb Bag
Expected outputs
- Cubic Yards: 1.3 yd³
- Bags Needed: 59
- Cubic Feet: 35 ft³
Known limitations
- This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
- Use the result as a planning estimate unless the calculator page states a stricter purpose.
Assumptions
- Length and width are in feet, while slab thickness is in inches.
- All dimensions must be positive, and waste cannot be negative.
- Bag counts use a fixed density approximation and should be treated as planning estimates.
Unit handling
- Length accepts values in ft.
- Width accepts values in ft.
- Thickness accepts values in in.
- Waste Factor accepts values in %.
- Premix Bag Size accepts one of the configured options.
- Cubic Yards is displayed in yd³.
- Cubic Feet is displayed in ft³.
Rounding rules
- Number displays use up to 2 decimal places in the calculator UI.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current concrete-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for Concrete Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.