Customer lifetime value (CLV) is the total value a customer brings to your business over the whole time they keep buying from you, not just on their first purchase. It is most useful measured as profit rather than revenue. In the UK it is usually shortened to CLV; software companies tend to say LTV.
How customer lifetime value works
The simplest method multiplies four things: the average spend per purchase, how many purchases a customer makes a year, how many years they stay, and your margin. Here is an illustrative example for a VAT-registered dog grooming salon in Bristol.
- Average visit: £54 including VAT, so £45 excluding VAT
- Visits per year: 6
- Average time as a customer: 3 years
- Margin after groomer time and products: 40%
Revenue over the lifetime is £45 × 6 × 3 = £810. Lifetime value in profit is £810 × 40% = £324. Leave VAT out, because it is collected for HMRC and never belonged to the business.
If customers subscribe or buy on a regular cycle, you can estimate the lifetime from your churn rate instead: the average customer stays roughly one divided by the churn rate. At 4% monthly churn, that is about 25 months.
That is historic CLV, worked out from what customers have already done. Predictive CLV uses models to estimate what a particular customer is likely to spend in future. At the time of writing (October 2026), GA4 offers predictive metrics for properties with enough purchase data, and many ecommerce platforms show a basic lifetime spend per customer.
Why it matters
CLV decides how much you can afford to spend winning a customer. The groomer above could pay £60 in advertising for a new client and still do well, even though that is more than a single visit earns. Comparing CLV with customer acquisition cost through the LTV to CAC ratio shows whether growth is profitable.
It also shows where to aim. If customers from local search stay three times longer than those from a discount promotion, the promotion is less valuable than its cost per sale suggests. And because a small share of customers often accounts for much of the value, knowing who they are helps with retention offers and with building ad audiences that resemble them.
It changes how retention spending looks, too. A thank-you offer that keeps a customer for one more year adds a full year of profit to their value, which is often far more than the same money would buy in new customers.
Common mistakes
- Using revenue instead of profit. A £1,000 customer at 10% margin is worth less than a £400 customer at 50%.
- Including VAT. It inflates every figure by up to a fifth.
- Guessing the lifetime. A business that is two years old cannot know that customers stay seven years.
- Relying on one average. Split CLV by product, channel and customer type to see the real spread.
- Treating CLV as fixed. Price rises, new products and changes in churn all move it, so recalculate it at least twice a year.
How to act on it
Export your order history, group customers by the month they first bought, and calculate what each group has spent and kept you in profit so far. Use the cautious figure, not the hopeful one. Then compare it with what you pay to win customers; the LTV and CAC calculator does the arithmetic and shows the payback period. Raising CLV through retention is often cheaper than lowering acquisition costs, and weighing the two against each other is part of my digital marketing strategy work.