The calculation chain
Methodology version 1.0 · Last reviewed September 2, 2026
- Measure the geometry. Convert dimensions or a known area into a consistent base area or volume.
- Show the raw requirement. Report the mathematical quantity before any planning adjustment.
- Apply an explicit allowance. Keep settlement, contingency or ordering allowance visible and editable.
- Convert material units. Use an exposed density, package volume or verified product yield where a conversion is required.
- Round only the purchase quantity. Round upward to whole bags, units or the supplier increment selected by the user.
Cost is calculated last from user-entered prices. A blank price never changes the material quantity.
Geometry and units
Rectangle, triangle, circle, semicircle and trapezoid areas use deterministic geometry. Irregular projects add positive sections and subtract marked cut-outs before depth is applied. Unit switching converts the same underlying quantities rather than running a different material formula.
Raw volume = measured area × project depth
Adjusted requirement = raw requirement × (1 + allowance ÷ 100)
Purchase quantity = adjusted requirement rounded up to the selected sell unit
Density, bags and supplier rounding
Volume and weight are different quantities. Gravel, sand, asphalt, topsoil and similar materials do not have one universal volume-to-weight conversion: moisture, grading, source and compaction can change bulk density. Where a planning density is offered, it remains visible and editable. The supplier's conversion for the exact material takes priority.
Bagged concrete uses manufacturer-published yield for the selected product, not a generic bag-weight formula. Landscape bags use the volume printed on the package. Supplier increments and minimums vary, so the calculators expose the ordering increment rather than presenting it as a fixed industry rule.
How assumptions are labelled
| Status | Meaning |
|---|---|
| Deterministic formula | Geometry or a defined unit conversion; no empirical material assumption is required. |
| Verified product data | A value transcribed from a named manufacturer document for a specific product. |
| Verified reference | A value or range checked against an identified technical or industry source. |
| Source-supported editable start | A useful starting value in a stated context, not a universal specification. |
| Planning default | An exposed convenience assumption where practices vary or no universal rule applies. |
| User supplied | A value entered or selected by the person using the calculator. |
Current source register
This first public register identifies selected consequential external values used by the current calculator set; it is not yet an exhaustive catalogue of every supporting reference. Each calculator's result also carries a calculation record and versioned provenance for the assumptions it used.
| Use | Source | Checked |
|---|---|---|
| Asphalt compacted planning density | Minnesota Asphalt Pavement Association asphalt calculator (110 lb per square yard-inch) | Aug. 30, 2026 |
| Concrete Mix package yields | QUIKRETE Concrete Mix Data Sheet 1101 | Aug. 30, 2026 |
| Post-setting Fast-Setting package yields | QUIKRETE Fast-Setting Data Sheet 1004-50; Sakrete Fast-Setting product data | Sept. 2, 2026 |
| Post-setting allowance starting point | Sakrete concrete calculators (editable 10% starting allowance) | Sept. 2, 2026 |
| Mulch depth starting context | University of Minnesota Extension | Sept. 2, 2026 |
Planning defaults that are not established universal standards are described as such in the calculation record. Product labels, current supplier information, plans and project specifications override general defaults.
Testing and release checks
Calculator engines are separated from their browser interface so the formulas can be regression-tested directly. Release checks cover representative geometry, validation, unit systems, allowances, rounding, optional-price neutrality, product yields, canonical routes, internal navigation, sitemap output and the production build.
Automated tests reduce implementation mistakes; they do not turn a planning estimator into engineering approval or verify the conditions of a real site.
Editorial and professional review status
JobsiteMeasure does not currently claim independent engineer, quantity-surveyor, horticulturist or other professional review for any calculator. A calculator may rely on professional or manufacturer sources without the calculator itself being professionally reviewed.
If independent review is added, the relevant page will identify the reviewer, qualification, review date and scope. Quantity calculators deliberately avoid selecting structural dimensions, reinforcement, soil bearing capacity, frost depth, code compliance or other design decisions that require project-specific judgment.
Updates and corrections
Source-backed data is stored with a source date and version identifier so later changes can be audited. A material change to a formula, default or product yield requires updated tests and a new data version.
JobsiteMeasure does not yet operate a public submissions inbox. If a result appears inconsistent, do not rely on it: recheck the inputs and assumptions, verify the quantity independently and follow the position on the Contact & Support page. A dedicated corrections route will be published before direct reports are accepted.
Ready to estimate? Choose a project calculator, inspect its assumptions and verify the purchase quantity with the supplier before ordering.
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