Reorder Point Calculator
Work out when to reorder stock. Enter average daily demand, lead time, and safety stock to get your reorder point, with the formula and a worked example.
The reorder point tells you the on-hand quantity at which to place a new order so stock arrives before you run out. It is the demand you expect during the lead time, plus a safety buffer for variability.
How it works
Multiply your average daily demand by the lead time to get expected demand during replenishment, then add safety stock. Keep demand and lead time in the same time unit.
The formula
Reorder point = (average daily demand x lead time) + safety stock. With no safety stock, you reorder exactly when expected lead-time demand is left on the shelf.
Worked example
At 10 units/day with a 4-day lead time and no safety stock, the reorder point is 10 x 4 + 0 = 40 units.
Frequently asked questions
What is a reorder point?
It is the inventory level that triggers a new purchase or production order, set so replenishment arrives roughly as you sell the last of your buffer.
How much safety stock should I add?
Size it to a target service level from demand variability. Use the safety stock calculator, then feed the result into this tool.
Does this handle variable lead times?
This is the basic deterministic form. If lead time varies a lot, increase safety stock to cover that variability.
Related tools
This is a planning estimate. Results depend on your inputs and assumptions; confirm against your own data before ordering.
- Demand and lead time use the same time unit.
- Average daily demand is stable over the lead time.
- Safety stock is supplied separately (see inventory.safety_stock.service_level).