About this site
EOQCalculator.com is a reference site for the Wilson economic order quantity formula and its standard variants (quantity discount, backorder, EPQ, multi-item joint). Built by Oliver Wakefield-Smith of Digital Signet. The math doesn’t change quarter to quarter; this site exists because the SERP for "eoq calculator" under-serves the buyer who needs to defend the answer to a CFO[1].
Why this site exists
Most existing EOQ calculators return a number. The buyer typically needs three further things the SERP fails to deliver: (1) the cost curve the number sits on, so they can see how flat the optimum is; (2) the sensitivity strip so they know whether the answer survives a 3-point swing in carrying cost; (3) the derivation footnote with primary sources, so they can cite it in a board pack. We deliver all three.
Author
Oliver Wakefield-Smith is the Founder of Digital Signet, a small London-based studio that builds reference and calculator sites for niche professional buyers. Background in software, operations research, and consumer-cost research. Reachable at the email link in the footer; corrections welcomed and credited.
What "math reviewed June 2026" means
Each of the five calculators (Wilson, quantity discount, backorder, EPQ, ROP) is hand-checked against worked examples from Silver / Pyke / Peterson (2017) and Nahmias (2009). The verification date is 21 June 2026. Re-verification will follow any change to the calculation code or any addition to the calculator set. We do not refresh "market data" because we don’t publish market data; the only date-sensitive content is the vendor-pricing references on the sources page, verified 20 June 2026.
What this site is not
Not consulting. Not a substitute for an ERP or planning system. Not a place to host proprietary SKU data; everything you enter into the calculators stays in your browser. For a planning system, see Cin7, Zoho Inventory, Fishbowl, or NetSuite; for consulting, any APICS-certified planner will do.