01 / Direct answer
What is a reorder point?
A reorder point is the inventory level at which you should review replenishment for an item. In the simple model used by ShopsInto, it covers the units you expect to sell while waiting for the supplier, plus any safety stock you choose to hold.
The threshold answers when to reorder. It does not answer how much to order. Purchase quantity still depends on factors such as expected demand, incoming orders, supplier minimums, pack sizes, storage, shelf life and available cash.
Oracle NetSuite documents the same basic relationship between demand, lead time and safety stock. See theOracle inventory documentation.
02 / Formula
Use demand during lead time plus safety stock.
Lead-time demand = average daily demand × supplier lead time in days
Reorder point = lead-time demand + safety stock
Keep the units consistent. If demand is recorded as individual units per calendar day, lead time should use calendar days and safety stock should also be individual units. Do not mix cases, pieces, weeks and days in the same calculation.
Use theReorder Point Calculatorwhen you want the arithmetic calculated in your browser.
03 / Worked retail example
Eight units a day, five days to deliver, twelve units of buffer.
Consider one product with these illustrative inputs:
- Average daily demand: 8 units
- Supplier lead time: 5 days
- Safety stock: 12 units
Lead-time demand: 8 × 5 = 40 units
Reorder point: 40 + 12 = 52 units
At 52 available units, the reorder threshold has been reached. At 60 units, stock is 8 units above the threshold. At 45 units, stock is 7 units below it.
52 units is the reorder trigger, not an instruction to order 52 units. The figures are an example, not a recommended stock target.
04 / Measure the inputs
Use records that describe the product you are actually replenishing.
Average daily demand
Start with units sold or used over a relevant period and divide by the number of comparable days. Check whether the item was actually available: recorded sales can understate demand when the product was out of stock.
Supplier lead time
Measure the time from placing the order until the goods are received and ready to sell. Use actual receiving history where possible rather than relying only on the supplier's best-case estimate.
Safety stock
Safety stock is an additional buffer for uncertainty. It may help when demand runs higher than normal or deliveries take longer than expected, but carrying more buffer also uses cash and storage space.
05 / Safety stock
A simple buffer method is not a universal safety-stock formula.
One common planning method is:
(maximum daily demand × maximum lead time) − (average daily demand × average lead time)
For example, maximum demand of 12 units per day and maximum lead time of 7 days, compared with averages of 8 units per day and 5 days, gives:
84 − 40 = 44 buffer units.
Treat this as one conservative planning method, not a universal rule or service-level guarantee. More advanced inventory models can use demand variability, lead-time variability and a chosen service level. Oracle documents an example of that more statistical approach in itsInventory Optimization calculations.
ShopsInto's calculator does not choose an ideal safety stock for you. Enter the buffer your own planning process supports.
06 / Changing conditions
Recalculate when demand or supplier timing stops looking representative.
A simple reorder point works best when the average inputs are useful descriptions of current trading. Promotions, holidays, seasonal peaks, new competitors, product launches, supplier delays and changing customer demand can all make an old average misleading.
Do not hide seasonality inside one annual average if the product behaves very differently across the year. Use a period that represents the decision you are making and record why that period was selected.
When supplier lead times vary materially, record actual order, dispatch, receipt and ready-to-sell dates so you can see both the typical delay and unusually slow deliveries.
07 / Small-shop records
Keep enough evidence to recalculate the threshold.
- Product and variant: calculate separately where sizes, colours or models sell differently.
- Daily or period sales: keep the units and dates used for the demand average.
- Stockout periods: note when recorded sales were limited because the item was unavailable.
- Purchase-order date: when the replenishment request was actually placed.
- Receipt / usable date: when the stock became available for sale.
- Current available stock: separate sellable units from damaged, reserved or unavailable stock.
- Incoming orders: check quantities already on the way before placing another purchase.
- Reason for the buffer: record the uncertainty the chosen safety stock is intended to cover.
08 / Common mistakes
Avoid inputs that make a precise-looking answer unreliable.
- Entering weekly sales as daily demand.
- Mixing calendar-day demand with working-day lead time without adjusting the basis.
- Mixing cases, packs and individual units.
- Using a promotional spike as normal demand without recording that context.
- Ignoring periods when the product was unavailable.
- Counting reserved, damaged or unsellable units as available stock.
- Ignoring purchase orders that are already in transit.
- Treating the reorder point as the quantity to purchase.
- Continuing to replenish an item simply because it still has a saved threshold.
If an item may no longer deserve replenishment, reviewDead Stock in Retailbefore treating its historical reorder point as an instruction to keep buying it.
09 / Review cadence
Review the threshold when the underlying evidence changes.
There is no universal number of days after which every retailer should recalculate every item. Review frequency should reflect the product's sales pace, seasonality, value, shelf life, supplier reliability and the cost of getting the threshold wrong.
Recalculate after meaningful demand changes, supplier changes, repeated late deliveries, major promotions, assortment changes or when the shop discovers that the recorded stock and physical stock no longer reconcile.
For stable products, a regular exception review can be more useful than constantly changing the threshold. Record the date, inputs and reason when you change it.
11 / Evidence and limitations
What this guide is based on.
Sources checked . The sources support the core reorder-point relationship, safety stock concept and the distinction between reorder timing and order sizing. The record-keeping sequence, review advice and worked example are ShopsInto guidance.
- Entering Inventory Management Details — Oracle NetSuite. Checked 16 October 2026. Documents reorder point as demand during lead time plus safety stock, and describes safety stock as a buffer for demand variation.
- Inventory Optimization Calculations — Oracle NetSuite. Checked 16 October 2026. Shows a more advanced safety-stock model using demand variability, lead-time variability and a service level. This supports treating simple buffer formulas as planning methods rather than universal rules.
- Reorder Point Defined: Formula & How to Use — NetSuite. Checked 16 October 2026. Explains that reorder point is primarily about when to reorder, not the quantity to purchase.
This simple model does not predict sales, supplier reliability, stockout probability or an ideal safety-stock level. It does not calculate purchase quantity. Review outstanding orders and your current trading context before ordering. Seehow ShopsInto researches guidanceand our disclosure.