Customer Lifetime Value for Ecommerce: The Formula, and Why We Measure It by Cohort

Customer lifetime value (CLV or LTV) is the total revenue, or better, the gross profit, a customer brings your brand over the whole time they keep buying from you. The classic formula is average order value × purchase frequency × customer lifespan. For ecommerce, we prefer cohort LTV: the average revenue per new customer within 30, 60 and 90 days of their first order, compared month by month.

Everyone wants a higher LTV.

Very few brands can tell you what theirs actually is. Or they have one number, calculated once, sitting in a pitch deck.

That number usually isn't wrong. It's just not very useful.

Here's how the standard formula works, where it misleads you, and how we measure lifetime value for the brands we work with.

By Emiel Dingemans, Founder of Magicianly

Updated October 2026

What Is Customer Lifetime Value?

Customer lifetime value is how much a customer is worth to your business over the whole time they keep buying from you. It's usually measured in revenue. It's more useful in gross profit.

CLV and LTV mean the same thing. Some people write CLTV. Same metric.

It matters because it sets the ceiling on what you can afford to pay for a customer. If a customer is worth $60 to you, you can't keep paying $80 to acquire one. If they're worth $200, the same $80 suddenly looks cheap.

What Is the Customer Lifetime Value Formula?

The most common formula multiplies three numbers:

Customer lifetime value = average order value × purchase frequency × customer lifespan

• Average order value (AOV): total revenue ÷ number of orders.
• Purchase frequency: number of orders ÷ number of unique customers, over a set period, usually a year.
• Customer lifespan: how many years the average customer keeps buying.

Say your AOV is $50, customers order 2 times a year on average, and they stick around for 3 years. $50 × 2 × 3 = $300.

That's revenue. To get closer to what a customer is actually worth, multiply by your gross margin. At a 60% gross margin, that $300 customer is worth $180 in gross profit.

Gross profit LTV = average order value × purchase frequency × customer lifespan × gross margin

That's the version you want when you compare LTV with what you pay to acquire customers. More on that below.

Why Does the Classic LTV Formula Mislead Ecommerce Brands?

Because it squeezes very different customers into one average, and one of its three inputs is a guess.

Four problems we see all the time:

1. 1Lifespan is a guess. Unless your brand has been around for years, you don't know how long customers stay. Change "3 years" to "5 years" and your LTV jumps 67% without a single extra order.
2. 2It mixes old and new customers. One blended number mixes customers who've been buying for years with customers who bought last week. It hides the trend you actually need to see: are newer customers becoming more valuable, or less?
3. 3The average hides the one-time buyers. For most brands, a lot of customers buy once and never come back. A smaller group of loyal repeat buyers pulls the average up and makes that leak invisible.
4. 4It's revenue, not profit. A customer who only ever buys with 30% off can look great on revenue and be worth very little.

So the classic formula is fine for a rough estimate. It's not a number we'd run a business on.

What Is Cohort LTV?

Cohort LTV is the average revenue a group of customers generates within a fixed number of days after their first order. A cohort is everyone whose first purchase happened in the same month.

Take every customer whose first order was in January. Add up everything they spent in their first 30 days, including that first order. Divide by the number of customers. That's January's 30-day LTV. Do the same at 60 and 90 days, and for every month after that.

30-day cohort LTV = revenue from the cohort's orders within 30 days of each customer's first order ÷ number of new customers in the cohort

That's also how Hiro, the analytics tool we use for client accounts, reports it: average revenue per new customer within a set number of days of their first purchase, including the first order.

We don't look at one overall lifetime value number. We look at cohort LTV, because it shows how fast revenue compounds after you've paid to acquire someone. It's one of the seven metrics we track to see whether retention is actually working.

What Does Each Cohort Window Tell You?

Each window shows whether a different part of your retention system is doing its job.

The trend matters more than any single number. If 90-day LTV is improving month over month, that's compounding. That's structural growth.

If 90-day LTV is flat, no amount of attributed email revenue on a dashboard changes that.

One rule: only compare cohorts at the same age. Last month's cohort doesn't have a 90-day number yet, so don't put it next to an older cohort's 90-day number.

How Do You Calculate Cohort LTV for Your Store?

You need order data with a customer ID and an order date. A Shopify order export works. So does most retention analytics software.

1. 1Group customers by the month of their first order. That's your cohort.
2. 2Count the new customers in each cohort.
3. 3Add up all revenue from those customers within 30, 60 and 90 days of each customer's first order. Include the first order.
4. 4Divide by the number of new customers. That's the 30, 60 and 90-day LTV for that cohort.
5. 5Compare cohorts at the same age. January's 60-day number against February's 60-day number, never against February's 30-day number.
6. 6Convert to gross profit before you compare it with CAC. Multiply by your gross margin, or subtract product costs if your margins vary a lot by product.

Use revenue after discounts and refunds if you can. Otherwise one heavy discount month can make a cohort look better than it is.

Want to go a level deeper? Split your cohorts by acquisition source or first product. Customers who came in through a big discount often behave very differently from customers who paid full price. We cover that in customer retention vs acquisition.

What Is a Good LTV to CAC Ratio?

There's no universal number. You'll see 3:1 quoted a lot as a rule of thumb, but what you can afford depends on your margins, your cash position and how fast customers pay you back.

Two things matter more than hitting a magic ratio.

Compare like with like. Use gross profit LTV, not revenue LTV. And use blended CAC: your total marketing spend divided by the total number of new customers. Not the CAC Meta or Google reports on its own.

Look at the time window. A ratio you only reach after five years and the same ratio within 90 days describe very different businesses. That's why we look at how quickly 30, 60 and 90-day LTV cover what you paid to acquire the customer.

If your 30-day LTV is improving and your first-to-second purchase rate is climbing, you can afford higher acquisition costs. Scaling ads gets less risky, your cash flow improves and your payback window gets shorter.

And here's the part most founders get backwards.

When growth stalls, the instinct is to push CAC down. Cheaper ads, more creatives, a new channel. That's the hardest lever in the business to move, and it gets harder every year.

The easier lever is what a customer is worth. Take a customer from one purchase to three and you've tripled what you can afford to pay to get them in the first place. Nothing about the ads changed. The customer did.

How Do You Increase Customer Lifetime Value in Ecommerce?

By making the first order worth more, getting the second order sooner, and keeping customers buying in between. These are the levers we pull most:

1. 1Make the first order worth more. Bundles, starter kits and a reason to buy more than one thing. For consumables, make subscription the obvious choice. A stronger first order is one of the cheapest growth levers you have.
2. 2Go after the second purchase in the first 30 days. If a customer is going to buy again, it usually happens soon after their first order. Don't wait for the winback flow to do it. Your first-to-second purchase rate is the number to watch.
3. 3Time post-purchase emails to real behavior. Help people use what they bought, then suggest the next logical product. For brands without a subscription, the window that matters is often around 20 to 40 days after the first order. Check your own average time between orders.
4. 4Remind people before they run out. If you sell something people finish, replenishment emails timed to when they actually run out are one of the simplest wins. And for consumables, subscription is the single biggest lever on lifetime value. Here's how to increase subscription LTV.
5. 5Give existing customers something new to buy. New products, new styles, new drops. If you don't give your customers something new, they'll get that feeling from a competitor.
6. 6Keep campaigns worth opening. For established brands, that's usually three to four campaigns a week, mostly product, education and brand content, with roughly one real sale a month. Training your list to wait for a discount lowers the value of every customer on it. Here's our campaign strategy beyond discounts.
7. 7Win customers back based on real behavior. Time your winback to when customers would normally reorder, not to a random 90-day timer.

What About Klaviyo's Predicted CLV?

It's useful, but it's a prediction, not your LTV. Klaviyo shows each customer's historic CLV (what they've already spent), predicted CLV (what Klaviyo expects them to spend over the next year) and total CLV (the two added together).

We use predicted CLV to spot customers worth protecting, and to avoid discounting people who were going to buy anyway. We don't use it to judge whether retention is improving. Actual cohort LTV does that. More in our guide to Klaviyo predictive analytics.

So How Should You Measure Customer Lifetime Value?

• Use the classic formula (AOV × purchase frequency × lifespan) for a rough estimate, and multiply it by your gross margin.
• Run the business on cohort LTV: average revenue per new customer within 30, 60 and 90 days of the first order, grouped by month of first purchase.
• Compare cohorts at the same age, and watch the trend, not one number.
• Judge LTV against blended CAC, in gross profit, over a time window.
• Grow it by making the first order worth more and getting the second order sooner.

Your ads decide what a customer costs. Your retention system decides what they're worth.