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Reorder-point calculator
The reorder point is the stock level at which you must order, not the level at which you run out. It is average daily sales multiplied by the days it takes to arrive, plus a safety buffer. Enter your numbers and the calculator does the arithmetic and the suggested order quantity.
How the calculator works
Reorder point = (average daily sales × lead time) + safety stock.
If you sell three units a day and the supplier takes seven days, you will sell about 21 units before the order arrives. The safety stock covers the week the supplier is late or a promotion runs; three days of cover adds nine units. The reorder point is 30: when the shelf falls to 30, order.
Suggested order = reorder point + (daily sales × review period) − on hand. The review period is how often you look at the shelf — a week in this example — so the order covers the time until the next check as well as the lead time. The calculator uses seven days.
Choosing the inputs honestly
Average daily sales is the number people guess wrong most often. Use the last four weeks of actual sales for the item, divided by 28, and ignore the one week with the promotion unless promotions are regular. If the item sells in bursts, use the median day rather than the mean, or add more safety stock.
Lead time is not the supplier's promise; it is the date the stock is actually on the shelf. Add the ordering day, the delivery window and the evening someone forgets to receive it. If your last three deliveries took 6, 9 and 14 days, use 10.
Safety stock is the cost of being wrong. A cheap item that customers will wait for needs less; a line that loses a sale every time it is out needs more. Three to seven days is a reasonable start for a shop with a weekly order.
What the number does not know
The formula assumes demand is steady and the supplier is roughly reliable. It does not know about seasonality, a customer who buys fifty at once, cash flow, or a minimum order quantity. Treat the result as a floor, not an instruction: if the supplier's minimum is 24 and the calculator says 9, order 24 and accept the extra cover.
It also does not replace the count. A reorder point computed against a book quantity that is wrong will order the wrong amount. Count before you trust the number, especially for the twenty items that matter most.
Putting it into the product
Mobile Inventory stores a minimum per item and puts anything at or below it on the reorder list. The suggested top-up is twice the minimum minus what is on hand — a deliberately simple rule that keeps a full lead time of cover without a forecast. Set the minimum to the reorder point this calculator gives you, and the list will do the remembering. If you want a different quantity, edit it before you order; the list is a suggestion, not a purchase.
For items with a supplier, the list can be grouped by supplier and turned into a draft purchase order on Pro. Read the reorder-list help article for the steps.
Worked example: a café's oat milk
A café sells 4 cartons a day, the supplier delivers in 5 days, the owner keeps 4 days of safety cover, and there are 18 cartons on the shelf. The reorder point is (4 × 5) + (4 × 4) = 36. The shelf is below it, so the suggested order is 36 + (4 × 7) − 18 = 46 cartons. The owner orders 48 because the supplier sells cases of 12 — and writes the minimum as 36 in the item, so the next check starts from the same rule.
Related tools and guides
- Printable inventory count sheet — get the on-hand number right first.
- How to run a stocktake on a phone — the full counting method.
- Cycle counting for small shops — keep the number honest between counts.
- Barcode label generator — label the shelf so counting is faster.