What is repeat purchase rate, and what actually moves it

The share of customers who came back inside a period you fix

Count the customers who've bought more than once. Divide that by the number of customers you have. Do it over a period you fix in advance, and count people, not orders.

The period is the whole argument. A rate measured over a brand's entire history will always look better than one measured over twelve months, because it's had longer to collect second orders. Fix the window. Then never move it.

Three different numbers all get called this

Ask three people in one company for the repeat rate and you'll get three answers, all of them arithmetically correct. Worth agreeing which one you mean before anybody is asked to improve it.

• Customers who ordered twice or more, over all time, which flatters an older brand
• Customers from one starting month who came back inside a year, which is the useful one
• Repeat orders as a share of all orders, which is a different metric wearing the same name

What it looks like on an account that works at it

The two post-purchase rows in that account are the ones doing this job. They reach somebody who has already paid, at the only moment when your brand is genuinely interesting to them. That's why they earn per recipient in a way a campaign can't.

Four things, and only one of them is an email

Let's be honest about this one: repeat rate is a product and operations number that email can help with. If the first order turns up late or the product disappoints, no amount of follow-up fixes it, and the follow-up reads as nagging.

• Whether the delivery and the unboxing matched what was promised
• Whether there is a sensible second thing to buy, and whether you told anybody about it
• Timing: reaching people when the first purchase is running out, not on a fixed monthly calendar
• Whether the second order is easier than the first, which is usually an account and checkout job

The email part is the post purchase flow, and it's worth building before any campaign calendar, because it runs for every customer without anybody scheduling it.

Not retention, not churn, not repeat order share

Retention rate asks whether a customer is still active. Churn asks who has left. Repeat purchase rate asks something narrower and more useful: did the first order lead to a second one. The glossary has the neighbouring terms, and the Shadow Foam write-up shows the whole quarter these figures came from.