How this site is sourced
EOQ math doesn’t change quarter to quarter. Wilson’s 1934 derivation is identical to Silver / Pyke / Peterson’s 2017 chapter and identical to what NetSuite implements in its lot-sizing field. Our methodology page is therefore deliberately short: the heavy work is per-page inline citations, not a central methodology dump[1].
Why inline marginalia
Most cost-calculator sites cite their sources in one place (a methodology page) because the market data they cover (vendor prices, salaries, tax rates) changes monthly and a single audit stamp covers it. EOQ math is different: the formula doesn’t change. What does change between pages is which textbook chapter or original paper backs a particular numerical or definitional claim.
So we put the citation where the claim lives - inline, as a small numbered superscript that resolves in the margin as a hex tag. On desktop the hex tags hang in the right rail like footnotes pinned to the page; on mobile they collapse to a footnote section at the page bottom. This mirrors the academic textbook convention rather than the SaaS landing-page convention.
What we audit
Math correctness, formula derivation, and citation accuracy. We do not audit market-data freshness, because we don’t publish market data. The sole vendor table (the sources page) carries verified-on dates for vendor pricing where we mention specific ERP / inventory products.
What "math verified June 2026" means
Each calculator (Wilson, quantity-discount, backorder, EPQ, ROP) was hand-checked against three worked examples from Silver/Pyke/Peterson and one from Nahmias. The math passed. The verification date is 21 June 2026. We will re-verify if and when we change the calculation code or extend the calculator set.
Named author
Oliver Wakefield-Smith, Founder, Digital Signet. Contact via the about page. Corrections welcomed and credited.