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Free tool

Churn window calculator

Stop guessing '90 days'. Measure how long your customers usually wait between orders and get thresholds that fit your store.

  • Free, no sign-up
  • Runs in your browser
  • Your file is never uploaded

Drop your Shopify orders CSV here

or . It is read on your computer and never uploaded.

Need the file? In Shopify admin go to Orders → Export → All orders → Plain CSV file. Step-by-step guide.

Want these groups updated automatically inside Shopify? Try WinBack free on the Shopify App Store.

Why one fixed number does not work

Coffee customers come back in weeks, furniture customers in years. This tool measures your own median reorder gap and suggests calling a customer drifting at about 2x that gap and at risk at about 3x. Read how to pick a churn window for the reasoning.

Put it to work

Use the thresholds to time reminder and win-back emails. WinBack measures the gap automatically inside Shopify and keeps every customer's risk of leaving up to date.

Questions

What is a reorder gap?
The number of days between one order and the next order from the same customer. The calculator measures every gap in your file and takes the median, so a few very late customers do not distort it.
Why 2x and 3x the median?
Customers do not reorder like clockwork. At twice the usual gap a customer is late enough to be worth a reminder; by three times the gap most customers who were coming back on their own already have.
How much data do I need?
At least 20 repeat orders for a rough answer, more for a reliable one. With fewer, the tool still shows a number but warns you.
Is my file uploaded?
No. The CSV is read in your browser and never leaves your computer.

Also try: RFM calculator · Repeat purchase rate