Inventory
Inventory Reorder Point Calculator
Work out the stock level at which to place your next order, so new stock arrives before you run out.
This is a maths-based calculator, not a fee calculator: every input is a number you enter yourself, and no platform fee is used. Your average daily sales, lead time, and safety stock come from your own sales records and your supplier, so the result works for any product and any marketplace.
Formula
Reorder point = (average daily sales × lead time in days) + safety stock. With the service-factor option, safety stock = service factor (z) × standard deviation of daily demand × square root of lead time in days. The reorder point is rounded up to a whole unit, because you cannot hold part of a unit.
How it works
Enter your average daily sales and your supplier's lead time in days. Then choose how to set safety stock: enter a buffer directly, or let the calculator work it out from a service factor if you know how much your daily demand varies. The calculator first works out demand during lead time, then adds safety stock, so the result covers both the expected wait and a buffer for surprises.
Worked example
A seller averages 10 units sold per day, with a supplier lead time of 14 days and a safety stock buffer of 35 units. Demand during lead time is 10 × 14 = 140 units. Reorder point = 140 + 35 = 175 units. So when stock on hand falls to 175 units, place the next order. At 10 units a day, those 175 units cover the 14-day wait (140 units) plus the 35-unit buffer.
How to read the result
If your stock on hand is above the reorder point, you can wait. If it has fallen to the reorder point, order now: the units you hold should last until the new delivery arrives, with the safety stock as your cushion. If you are already below the reorder point, order as soon as you can, because you are already eating into that cushion.
FAQs
What is the reorder point?
The reorder point is the stock level at which you should place a new order. It covers the units you expect to sell while the new order is on its way, plus a safety stock buffer for unexpected sales or delays. When your stock on hand falls to this level, order now, not when you run out.
How do I choose my safety stock?
Start with a simple buffer you can afford to hold, such as two to seven days of average sales, and adjust it from experience. A larger buffer protects you against stockouts but ties up more cash in stock; a smaller buffer frees cash but risks running out if sales spike or a delivery is late.
How does the service-factor option work?
The service-factor option calculates safety stock as the service factor (z) multiplied by the standard deviation of daily demand, multiplied by the square root of the lead time in days. For example, a 95% service level uses a factor of 1.65. Use it when you have daily sales records and can estimate how much daily demand varies.
Does the reorder point tell me how much to order?
No. The reorder point tells you when to order, not how much to order. Your order quantity is a separate decision based on pack sizes, supplier minimums, storage space, cash flow, and how often you want to reorder.
What if my lead time or sales change?
Recalculate the reorder point whenever either changes. A longer lead time or higher daily sales raises the reorder point, because you need more stock to cover the wait. Check the result each time you change supplier, add a product, or see a lasting shift in sales.
Can I use this calculator for any product?
Yes, because every input is one you enter yourself: average daily sales, lead time, and safety stock. It works for any product sold online, and it does not use any platform fee, so it is not tied to Etsy, eBay, Amazon, or any other marketplace.
Stand: October 2026. Pure arithmetic — no platform rate is used; enter your own figures.
Disclaimer: Results are estimates and general information only. Reorder timing depends on your actual sales and supplier lead times, so check them before you place an order.
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