RightFiguresLead-time demand plus the safety stock you enter
Daily demand times the lead time is the expected demand while an order is outstanding. A fraction of a unit rounds that demand up to the next whole unit. The reorder point is that whole number plus the safety stock you type.
This is not the unit price calculator, which divides a price by a quantity. It is not an order quantity, and it does not choose the safety stock. The business break-even calculator counts units that cover a fixed cost. The profit margin calculator compares a cost with a selling price.
USDA Rural Development SR-41 sets a reorder point equal to the safety level plus the units required during lead time. The GAO inventory guide includes lead-time stock and a safety quantity in a reorder point. This page does not use a service level to size that safety quantity.
10 units a day
10.00 units a day, 7 days, and 20 units of safety stock are 70.00 units of lead-time demand. The reorder point is 90 units. The product is already a whole number, so nothing is rounded up.
10.50 units a day for 7 days is 73.50 units. With 0 safety stock, the reorder point is rounded up to 74 units.
13 units a day
The USDA bagged-feed example is 13 units a day, a 3-day lead, and safety stock of 10. Lead-time demand is 39.00 units. The reorder point is 49. The ceiling does not change that exact product.
0.00 units a day leaves the reorder point equal to the safety stock. A lead time of 0 days does not add demand. 0.01 units a day for 1 day rounds up to 1 unit. The same demand for 100 days is 1.00 unit exactly, so it is not rounded up. All three inputs at zero produce a reorder point of 0 units.
Above 100,000,000 units
1,000,000.00 units a day for 365 days is above 100,000,000 units. So is 0.01 units a day for 1 day added to 100,000,000 units of safety stock. Neither result is shown. 100,000,000 units of safety stock, with no demand and no lead time, is shown. That number is the cap, not a recommendation.
Frequently asked questions
Does this page choose the safety stock?
No. Safety stock is the number you enter. A service level and a standard
deviation are not inputs.
Is the reorder point an order quantity?
No. It is the stock level that includes lead-time demand and the safety stock
you entered. It does not say how many units to buy.
Are the quantities sent to analytics?
No. Analytics may record that this calculator ran. Demand, lead time, safety
stock, and the reorder point stay in this browser.
Sources & review
- Retail Supply Chain Management (SR-41) — USDA Rural Development
- Economics of Inventory Control — U.S. Government Accountability Office
Last reviewed: . The formula is reproduced above so you can check the math independently.
Educational estimate only. This page does not predict supplier delays or choose an order quantity.