Purchase frequency is the average number of times a customer buys from you within a set period, usually a year. You calculate it by dividing the number of orders in the period by the number of unique customers who placed them: 1,200 orders from 800 customers gives a purchase frequency of 1.5.
How purchase frequency works
The arithmetic is simple. The meaning lies in the choices you make around it.
- The period. A year suits most shops. A coffee subscription might look monthly; a furniture retailer might need two or three years to see any repeat buying at all.
- Who counts as a customer. Guest checkout is the usual trap. If the same person checks out as a guest three times with slightly different details, your platform may record three customers with one order each, and frequency looks lower than it really is. Match on email address where you can.
- What counts as an order. Decide whether to exclude refunded, cancelled, staff and wholesale orders before you compare periods.
A companion figure is time between purchases: the typical gap between one order and the next for customers who return. Frequency tells you how often people buy; the gap tells you when to expect the next order, which is what you need to time emails and offers.
Purchase frequency sits alongside average order value as one of the two levers behind revenue per customer. Multiply them and you have annual spend per customer, which feeds directly into customer lifetime value.
Why it matters
Most growth plans concentrate on finding new customers, which is the most expensive way to grow. Raising frequency means earning more from people who already know and trust you, at a fraction of the advertising cost. A shop with 2,000 customers buying 1.4 times a year that moves to 1.6 has added about 400 orders a year without a single new customer.
Frequency also tells you what kind of business you run. Products bought every month, such as pet food, skincare or coffee, can justify spending more to win a first order because repeat sales recover the cost. Products bought once every few years, such as a sofa or a wedding dress, cannot, so the first order has to pay for its own acquisition. Getting this wrong is one of the quickest ways to lose money on paid social.
Common mistakes
- Comparing mismatched periods. A UK retailer comparing October to December with January to March is mostly measuring Christmas.
- Looking only at the average. A frequency of 1.5 might mean most people buy once and a loyal few buy ten times. Split customers into one-time and repeat buyers before drawing conclusions.
- Chasing frequency with discounts. Constant offers lift order numbers and quietly cut margin. Check profit per customer, not just orders.
- Ignoring the product’s natural cycle. Nobody needs a new mattress every quarter. Set targets that match how the product is actually used.
How to act on it
Export a year of orders with customer email, order date and value. Work out frequency for the whole customer base, then separately for customers acquired through each main channel. You will often find one channel brings in people who come back and another brings bargain hunters who never return.
Next, measure the typical gap between first and second order. That second order is the hardest to win, so build a post-purchase email sequence timed to arrive just before the gap closes: care instructions, a refill reminder, a genuinely related product. For consumables, a subscribe-and-save option often does more than any campaign.
Track frequency monthly as a rolling twelve-month figure so seasonal swings do not mislead you. If you want a plan built around repeat purchases rather than constant acquisition, that is part of my digital marketing strategy and consulting work.