Inventory reorder-point calculator: questions and guides
Each guide here answers one question with a practical example, then takes you to the tool to try it yourself. Guides: 15.
Questions
- How to calculate your reorder pointHow to work out the stock level at which to order from your supplier, from average daily sales, lead time and safety stock, with a worked example.
- I import from a supplier in China by sea: how do I work out the lead time to use for my reorder point?Lead time is not the sailing days. It runs from sending the order until goods are ready to sell: production, sea freight, clearance and delivery. See how far it moves.
- My sales double in Ramadan and my supplier slows down before Eid: how do I choose safety stock for that season?The calculator assumes steady demand, so run the season on its own: its average sales, its busiest day and the longest delay you saw last season. With numbers.
- My supplier delivers the same day, so why is my reorder point exactly equal to my safety stock?A zero lead time means nothing sells while you wait, so the reorder point is just the safety stock. But is same-day delivery really zero? A one-day example.
- My store report only gives me monthly sales: how do I turn that into the average daily demand the calculator needs?Divide units sold by the days the product was actually in stock, not every day of the month, or the reorder point comes out too low. A worked example with stockout days.
- My stock has fallen below the reorder point but an order is already on its way: should I order again?Compare the reorder point with stock on hand plus stock already ordered, not the shelf alone. A worked example shows when a second order doubles up and when it is due.
- One of my products sells only two a week: how do I get a sensible reorder point for such a slow item?Enter daily demand as a decimal and the calculator rounds the point up to whole units. A slow-seller example, and why safety stock matters more than demand here.
- I sell through Amazon FBA: what should my lead time include before stock becomes sellable at the fulfilment centre?Lead time ends when stock is sellable, not when it reaches you. With FBA, add inbound shipping and check-in at the fulfilment centre. See what ten extra days do.
- Why does the derive-from-maximums option give me a huge safety stock, and when is that too cautious?The rule multiplies your worst day by your worst delay, two events that rarely coincide, so safety stock can be many times normal usage. When that is too cautious.
- I get an error that my maximum daily demand is below the average and no safety stock is calculated: what did I enter wrong?A maximum cannot be below its own average, so the calculator refuses rather than give a negative safety stock. Usual causes: swapped fields or mixed periods.
- My supplier quotes 5 working days but my shop sells every day: do I enter lead time in working days or calendar days?Use the same kind of day in both fields: if daily sales cover every day of the week, convert the supplier's working days to calendar days. An example with a weekend.
- I order from my supplier on the first of every month: is ordering at a reorder point better than a fixed date?A reorder point brings orders forward in busy weeks and holds them back in quiet ones; a fixed date is simpler but can run dry. A busy-month example and how to use both.
- Are my sales figures and supplier lead times saved or sent anywhere when I use the reorder point calculator?Your sales speed and supplier lead times are what competitors would love to know. The calculator runs in your browser, sends nothing and never connects to your store.
- I sell the same product on my own store and on Noon from one shared stock: how do I calculate the reorder point?If both channels ship from the same stock, add their daily sales into one figure. If part of your stock sits in the marketplace's warehouse, calculate it separately.
- What number should I set as the low-stock alert in my inventory app or spreadsheet?Set the reorder point in whole units as the alert level, so the alert fires while you still have enough for the wait and the buffer. When shelf-only alerts mislead.