ShopsInto / free retail tools
Reorder Point Calculator
Your reorder point is the stock threshold at which to review a new order: average daily demand × supplier lead time + safety stock. This inventory reorder point calculator tells you when to reorder inventory. It does not determine how much to order.
Measure / replenishment
Find your stock threshold.
Use one product and the same unit of stock throughout. All three main inputs are required; zero is allowed.
Calculations stay in this page. Inputs are not saved or sent by the calculator.
Transparent arithmetic
The reorder point formula.
Lead-time demand = average daily demand × supplier lead time in days.
Reorder point = lead-time demand + safety stock.
A small-retail worked example
A shop sells an average of 8 bottles per day. Its supplier takes 5 days to deliver usable stock, and the shop chooses 12 bottles of safety stock. Lead-time demand is 8 × 5 = 40 bottles. The reorder point is 40 + 12 = 52 bottles.
At 52 available bottles, the threshold has been reached. At 60, stock is 8 bottles above it; at 45, stock is 7 bottles below it. The 52 bottles are a reorder trigger, not the quantity to buy. These illustrative inputs are not recommended targets.
Average daily demand describes normal daily sales, lead time covers the wait for usable stock, and safety stock is your chosen buffer. The calculator does not estimate an ideal safety stock.
What this result means.
With current available stock supplied, the calculator compares it with your unrounded reorder point:
- Above: the threshold has not been reached under these inputs.
- At: the threshold has been reached.
- Below: the threshold has been passed.
At or below the threshold, review replenishment and any outstanding orders. This is a planning signal, not an automatic purchasing instruction. Without current stock, the result gives only the threshold.
Results display up to four decimal places where needed. Status uses unrounded values. If you count indivisible items, round a fractional threshold upward when applying it. Decimal inputs can be useful for products measured by weight or volume.
Common input mistakes.
- Entering weekly sales as daily demand, or mixing calendar days with working days. Demand and lead time must use the same day basis.
- Mixing cases and individual units, or entering inventory value in money instead of units.
- Using an unusually quiet or busy period as the normal average. Stockouts can hide unmet demand in recorded sales.
- Counting reserved, damaged or unsellable stock as available. Check your stock records before comparing.
- Leaving safety stock blank when you mean zero. Enter 0 explicitly; a missing value is not assumed to be zero.
Reorder point vs order quantity.
Reorder point answers when to reorder. Order quantity answers how much to order. Decide quantity separately using outstanding orders, expected demand, supplier minimums, pack sizes, storage, shelf life and available cash.
A consistent threshold can help you plan to avoid stockouts and spot excess stock, but it cannot guarantee either outcome. A threshold alone does not justify buying more stock.
Assumptions and limitations.
This simple model assumes reasonably steady demand and a representative supplier lead time. Promotions, seasonal changes and delivery delays can make actual demand or waiting time different.
Current stock is a snapshot, not inventory position. The comparison does not add incoming purchase orders or subtract backorders. Review those separately before ordering to avoid duplicating a purchase.
The tool does not calculate an order quantity or an ideal buffer. It does not predict sales, supplier reliability or stockout risk. Zero demand or zero lead time produces lead-time demand of zero; check that this reflects your situation. Review your inputs as trading conditions change.