Subscription LTV vs ecommerce LTV

Most LTV calculators online offer one formula. That formula assumes you know how many years a customer stays, which most repeat purchase businesses do not, and it ignores churn entirely, which is the one number subscription businesses actually have.

The result is a figure that flatters one type of business and confuses the other.

Here is how the two actually differ, and which one you should be using.

The two shapes of ecommerce business

Repeat purchase. Customers place separate orders whenever they feel like it. There is no commitment, no renewal date, and no cancellation event. Most DTC stores and non-subscription Shopify brands sit here.

Subscription. Customers commit to a recurring charge and stay until they actively cancel. Recharge-style businesses, boxes, replenishment programmes.

The difference is not cosmetic. It changes what you can measure, and therefore what you can trust.

The repeat purchase formula, and its weak point

LTV = Average order value x Orders per year x Years as a customer

Two of those three inputs are solid. You know your average order value, and your purchase frequency is recoverable from order data with a bit of work.

The third input is the problem.

“Years as a customer” is almost never measured. It is estimated, and it is estimated by people who have a natural optimism about their own business. Ask a founder how long a typical customer sticks around and you will usually get a number that describes their best customers rather than their average one.

There is also a structural difficulty. In a repeat purchase business, nobody tells you they have left. There is no cancellation. A customer who has not ordered in seven months might be gone, or might be about to order tomorrow. You only find out in hindsight.

This is why repeat purchase LTV should be treated as a working estimate that you revisit, rather than a fact. Calculate it, write it down, and check it again in ninety days. The trend will tell you more than the number.

The subscription formula, and why it is more trustworthy

Implied lifespan in months = 1 / (Monthly churn rate / 100)
LTV = Monthly subscription price / (Monthly churn rate / 100)

At £30 a month with 8 percent monthly churn: £30 divided by 0.08 is £375, and the implied lifespan is 12.5 months.

The advantage here is that churn is an event you can count. Someone cancels, and your billing system records it. You are not estimating how long people stay, you are deriving it from something you measured.

If you do not currently track churn, the calculation is straightforward:

Monthly churn rate = (Customers who cancelled last month / Active customers at the start of the month) x 100

That is one number, once a month, from data you already have.

Why the difference matters commercially

The two formulas respond to improvement in different ways, and this is where it gets interesting.

In the repeat purchase formula, extending customer lifespan by 20 percent increases LTV by 20 percent. The relationship is linear.

In the subscription formula, it is not. Because LTV is price divided by churn, reducing churn produces a disproportionately larger gain. Take the £30 at 8 percent example. Improve retention by 20 percent, so churn drops to 6.4 percent, and LTV goes from £375 to £469. That is a 25 percent increase from a 20 percent improvement.

Push further and the effect grows. Halving churn from 8 percent to 4 percent does not increase LTV by 50 percent. It doubles it.

This is the mathematical reason subscription businesses should be more obsessed with retention than anyone else, and why churn is the single number worth putting in front of everything else.

If you run both

Plenty of businesses sell subscriptions alongside one-off orders. If that is you, resist the urge to blend.

Calculate two numbers and keep them separate. Subscribers and one-off buyers behave differently, cost different amounts to acquire, and respond to entirely different retention work. A blended average tells you about a customer who does not exist.

Where blending is useful is in acquisition decisions, and even then only if you also know the split. Knowing that a subscriber is worth £375 and a one-off buyer is worth £90 tells you exactly how much a channel that produces subscribers is worth relative to one that does not.

Which number to watch

For subscription businesses, churn, tracked monthly, watching the direction as much as the level. A churn rate of 5 percent that has been falling steadily for six months is a healthier signal than 3 percent that has been rising.

Watch where in the lifecycle it clusters, too. High first-month churn is an onboarding problem. High three-month churn usually means a gap between what acquisition promised and what the product delivers. High annual churn tends to be a value perception problem that pricing or communication can address.

For repeat purchase businesses, repeat purchase rate is the better early signal. The proportion of customers who buy a second time tells you whether the first thirty days are working, long before an LTV estimate would show it.

Either way, one number, once a month, reviewed before you look at anything else.