Open the calculator → Pairs with How to Calculate Safety Stock for the underlying formula.
What it computes
Enter your average and maximum daily sales alongside your average and maximum supplier lead time, and the calculator returns two numbers: your safety stock (the buffer quantity) and your reorder point (the on-hand inventory level that should trigger a new purchase order — safety stock plus expected demand during the average lead time).
Getting good inputs, not just fast ones
The calculator is only as accurate as what you feed it. Pull your "maximum" figures from actual history — your true worst single-day sales and your true longest recent lead time — rather than rounding up from a gut estimate or your supplier's quoted average. See How to Calculate Safety Stock for exactly where to source each input and why the "maximum" framing matters more than it looks.
Reading the output
If the reorder point the calculator returns is higher than your current on-hand inventory for a given SKU, you should already have placed a reorder. Treat that as an immediate action item, not just informational — see How to Prevent and Recover From Stockouts if you're already past that point.
When to re-run it
Re-run the calculator whenever any input changes meaningfully: a new sales high, a supplier lead-time change, a seasonal shift, or simply on the recalculation schedule you've set (see the checklist in How to Calculate Safety Stock). A number calculated two quarters ago on outdated sales data isn't protecting you against today's demand.