Reorder Point & Safety Stock Calculator

The problem this kills

Most reorder points are gut-feel numbers somebody typed into the ERP years ago. They were never recalculated when demand shifted, when a supplier's lead time crept up, or when a SKU went seasonal. The result is the worst of both worlds: you stock out on the items customers actually want, while cash sits frozen in shelves of slow movers you over-ordered "just in case."

The math to fix this is well understood - reorder point, safety stock, and economic order quantity. But running it properly across hundreds or thousands of SKUs in a spreadsheet is brittle, error-prone, and nobody trusts the result enough to push it back into the ERP. So the gut-feel numbers stay.

What you'll build

A small internal web app that does the boring math correctly and safely:

• Import your demand/usage history from a CSV or Google Sheet.
• Compute, per SKU, the reorder point, safety stock, and economic order quantity (EOQ) at a service level you choose (say 95%), using your supplier lead times and lead-time variability.
• Show each recommended value side by side with the current value, with the change highlighted.
• Flag SKUs that don't have enough history to trust, and handle lumpy or seasonal demand sensibly instead of producing nonsense.
• Let a planner review the recommendations and approve exactly which ones to apply.
• Export the approved changes as a clean CSV in the column layout your ERP expects - and log who approved what, and when.

What's inside the Implementation Plan

The plan is a single markdown file you paste into Claude Code (a free AI coding assistant). It builds the whole tool for you, step by step, pausing for your input where it matters.

It opens by interviewing you about your business - your SKU naming, where your demand history lives, how lead times vary by supplier, your typical and peak volumes, what service level you target, and the messy exceptions you already know about. It reflects a short tailored spec back to you for a thumbs-up, then shapes the data model, the formulas, and every later build step around your answers - so you get a tool fit to your operation, not a generic calculator.

From there it walks through: setting up the project, building the import, implementing the ROP/safety-stock/EOQ math (including the handling of lumpy and seasonal demand), the review-and-approve screen, the CSV export for your ERP, and the audit trail. Every build step ends with a ready-to-copy prompt.

The governance it includes (this is the point)

This isn't a throwaway spreadsheet macro. The plan bakes in the controls that make a tool safe to run on real inventory:

• Login so only your team can use it.
• Row-level security so each organization only ever sees its own data.
• A human approval gate - the tool recommends, a planner approves, and only approved values make it into the export. Nothing is written to your system of record automatically.
• A complete audit trail - who approved which SKU's new parameters, the old value, the new value, and the timestamp.
• Duplicate guards - the same SKU + parameter version can't be applied twice.

Who it's for

Inventory planners, demand planners, and purchasing teams who are tired of defending numbers they didn't really calculate - and who want a repeatable, auditable way to set replenishment parameters without waiting on IT or a six-figure planning module.

You've got this. Open the plan, paste the first prompt, and let the agent interview you.