Know when to reorder a part and how much buffer to hold. Use the statistical service-level method if you know your demand swings, or simple min/max if you just know your worst case — plus EOQ to size the order itself. Free, no signup — nothing leaves your browser.
Find when to reorder and how much buffer to hold, so you never stock out — or over-stock.
You're computing this one part at a time in a spreadsheet. Fabbric runs MRP across every part — watching real usage and lead times — and tells you what to reorder, and how much, automatically.
See how Fabbric works →Every stockout has the same anatomy: the part ran out while the replacement order was still in transit. So the reorder point isn't about how much you use — it's about how much you use during the lead time, plus a buffer for the days when usage spikes or the delivery runs late. That buffer is safety stock, and it's the difference between the min/max guess most shops carry and a number you can defend.
The statistical method sizes that buffer from your actual variability: how much daily demand swings, how much lead time swings, and how often you're willing to run out (a 95% service level accepts roughly one stockout in twenty cycles). More variability or a higher service level means more buffer — the math makes the trade-off visible instead of hiding it in a gut-feel max. And EOQ answers the follow-on question: once you've hit the reorder point, how much should the order be? Order too little and you pay ordering costs constantly; too much and cash sits on the shelf. EOQ is the break-even between the two.
This calculator does one part at a time — useful for your A-items, the parts that stop jobs. Doing it across every part, with live usage instead of estimates, is what an MRP module is for.