Editorial Policy

This policy governs how figures and claims on this site are sourced, checked, and corrected. It exists so readers can judge our reliability, not take it on faith.

How we source figures

Every numeric constant used by a calculator is stored as a typed sourced value: the figure, its unit, and the named standard or datasheet it comes from. We prefer primary sources, the standards themselves and manufacturer datasheets, and we cite the specific table or section, not a general reference. The complete list is on the sources page, generated at build time from the same data the calculators use, so what you read is what the math runs on.

When two credible sources give different figures, we present both and explain the difference rather than silently averaging them. When a figure is not yet confirmed against a primary source, we mark it as unverified in the data and do not present it as settled.

We do not reproduce paywalled standards

Standards from bodies such as ASTM, CMHA, and TMS are copyrighted, and several are sold. We cite and link to them and quote specific numeric values with attribution, but we do not reproduce their tables or prose text. Where you need the full text, we point you to the publisher.

How corrections are handled

If you believe a figure is wrong, tell us via the contact page with the source you are relying on. Because our data lives in version control, a correction is a tracked change with a history: we update the constant, the change flows automatically to the affected calculators and to the sources page, and the unit tests confirm nothing else moved unexpectedly. We aim to fix confirmed errors promptly and to be transparent about what changed.

Independence

Product names appear only where a figure genuinely comes from that product’s datasheet (for example, bag yields). Naming a product is attribution, not endorsement.