Terms of Use
The terms these free engineering calculators are offered under, and the limits of what their results mean.
Free to use
You may use these calculators for personal, academic, and commercial work at no cost, including in a professional engineering context. No licence, attribution, or permission request is required to use a result. If you want the underlying formulas in your own software, use the open-source formulab library directly rather than scraping this site.
Provided without warranty
The tools are provided as they are, with no warranty of any kind, express or implied. Despite the verification and automated checks described on the methodology page, we cannot guarantee that every result is correct for every input, edition of a standard, or jurisdiction. You are responsible for confirming any result before acting on it.
Not a substitute for engineering judgement
These are screening and estimation aids. They do not replace the governing standard, a competent engineer, a physical measurement, or a regulatory authority. This matters most for safety-related calculations — heat stress exposure, arc flash energy, fall clearance, structural and load limits — where a result should be treated as a first indication and confirmed by a qualified person before anyone relies on it.
Standards are cited, not reproduced
Where a tool names a standard, it identifies the source of a formula or a published value. The standards themselves are the property of their issuing bodies and are not redistributed here. If your work requires the authoritative text, obtain it from the issuing organisation.
Changes and availability
Tools, formulas, and reference values may change as standards are revised or as errors are found and corrected. No availability or uptime is guaranteed. Questions, corrections, and takedown requests: [email protected].