Lost Sales Calculator
How much revenue walks away while you are sold out? Put your numbers in.
What are lost sales from stockouts?
Lost sales are the orders you would have taken if the product had been in stock. They never show up in your reports, because the shopper simply leaves. That makes stockouts one of the most expensive problems a store can have without noticing.
How to calculate lost sales
The basic formula multiplies your normal sales rate by the time you were out of stock:
Lost revenue = units sold per day × average price × days out of stock × number of products
For example, a product that sells 6 units a day at $45 and is out of stock for 8 days a month loses 6 × 45 × 8 = $2,160 per month. Five products like that add up to $10,800.
How to recover part of it
- Collect demand while sold out. A notify-me form on the product page keeps the shopper instead of losing them.
- Alert fast when stock returns. The first hour after a restock is when intent is highest.
- Take pre-orders. If you know when stock lands, let people pay now with a deposit.
- Reorder by demand. Waiting lists per variant tell you exactly what to buy more of.
WaitCherry does all four, with forms that match your theme. See back in stock alerts.
Frequently asked questions
What is a stockout?
A stockout happens when a product or variant has zero sellable inventory, so shoppers who want it cannot buy it.
How accurate is this calculator?
It is an estimate based on your own numbers. Use your real daily sales and stockout days from Shopify analytics for the best result.
How much of the lost revenue can a waitlist recover?
It depends on your product, audience and how quickly you restock. The recovery rate is an input you control, so you can model conservative and optimistic cases.