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Editorial Policy

Accuracy first

Every calculator and guide is written to help someone buy the right amount of material. Numbers come from cited industry and manufacturer sources (see our methodology), and every calculator is tested against hand-worked examples before it is published.

Written and checked by people

Pages are written and reviewed by a person. We don’t publish pages generated in bulk, and we don’t make a separate page for every size or city just to catch searches. One good calculator per job is the rule.

Updates and corrections

  • Each calculator shows the date it was last checked.
  • When we find or are told about an error, we fix it, re-run the tests and update the date.
  • Material and price information is reviewed at least once a year, and sooner when manufacturers change their published data.

Independence

No supplier or manufacturer pays for placement or reviews our content before publication. If we ever add advertising or affiliate links, they will be labelled, and they will never change a calculator’s result.

Contact

Corrections and suggestions are welcome through our contact page.