Sources & References Policy
Last updated: July 26, 2026
How we choose and cite authoritative sources.
Source selection
We prefer primary standards: WHO health guidelines, established financial formulas, MDN for web APIs, and RFCs for encoding standards.
On-page citations
Each calculator page includes a Sources & references section with links where available.
Suggest a source
If you believe a better reference exists, email us via the contact page with the tool name and URL.