LTV CAC: Run the Numbers and Know What to Do Next

What Is LTV CAC?

Two numbers decide whether growth pays.

LTV CAC is a ratio that compares what a customer is worth over their lifetime with what it cost to win them. Shopify calls 3:1 a good ratio and puts typical acquisition cost between $127 and $462, depending on industry. A store with a $300 lifetime value and a $100 acquisition cost sits at 3:1.

Customer lifetime value (LTV) is the total a customer spends, or the profit they generate, across their time with you. Customer acquisition cost (CAC) is what you spent to win them. Divide LTV by CAC and you get the ratio.

Shopify's customer lifetime value guide names 3:1 as the target. Its customer acquisition cost guide adds that a ratio above the 3:1 to 5:1 range can mean you are not investing enough in growth.

One widely read source for the 3:1 idea is written for SaaS, not ecommerce. The For Entrepreneurs SaaS Metrics guide says the best SaaS businesses have a ratio higher than 3, and many recover their CAC in 5 to 7 months. It calls these guidelines and says there are situations where it makes sense to break them. An ecommerce store has different margins and buying patterns, so the ratio needs a second check.

This page is a walkthrough. You will run the calculation for three example stores, turn the answer into a spending ceiling, and see what to fix first. For the formula and its common errors, read our LTV CAC formula guide. For industry benchmarks, see the CAC to LTV ratio guide.

What Numbers Do You Need Before You Run LTV CAC?

Six inputs. Most are already in your store.

Run LTV CAC on six inputs: acquisition spend, new customers, average order value, orders per year, lifespan in years and gross margin. Pull all six from the same 12-month window. Shopify's CLV method multiplies order value, frequency and lifespan, so gross margin is the one extra input that turns revenue into profit.

Two inputs cause most of the trouble.

New customers versus orders. If 1,000 orders came from 700 people and 400 of them were first-timers, your denominator is 400. Divide spend by orders and you understate CAC.

Lifespan. With less than a year or two of history, lifespan is an estimate. Start with a cautious number and update it as cohorts age. Our CLV calculator guide shows how to estimate it for a newer store.

For the cost side, the cost per acquisition guide lists every line that belongs in CAC. The free CAC calculator does the division once you have the totals.

How Do You Calculate LTV CAC for Three Kinds of Store?

Same steps. Three very different answers.

Three illustrative stores run through identical steps land at 5.1:1, 2.7:1 and 2.6:1 on revenue LTV, but only 3.6:1, 1.5:1 and 1.3:1 once gross margin is applied. These figures are invented for demonstration, not benchmarks. The gap between the two rows is the point: revenue LTV flatters every store.

Follow these five steps for your own store:

1. Fully loaded CAC = total acquisition spend / new customers.
2. Revenue LTV = average order value x orders per year x lifespan in years.
3. Margin LTV = revenue LTV x gross margin.
4. LTV CAC = LTV / CAC. Run it on both revenue LTV and margin LTV.
5. Payback = how many orders it takes for cumulative gross profit to cover CAC.

Here they are for three example stores. All numbers are illustrative.

Read the revenue row alone and Store A looks excellent, Store B looks close to the line, and Store C looks weak. Read the margin row and the picture sharpens. Store A clears 3:1. Stores B and C are both well below it.

If you quote a benchmark, check which version of LTV it uses. Shopify's formula multiplies revenue, while margin-based versions sit lower. Comparing a margin ratio to a revenue benchmark makes a healthy store look weak. Our CLV formula guide covers the margin adjustment in full.

Not sure what your fully loaded CAC is? Run it through the free CAC calculator. Two minutes. No signup required.

Why Can a Low LTV CAC Ratio Still Be a Healthy Store?

Because the ratio ignores timing.

Store B and Store C post similar margin ratios, 1.5:1 and 1.3:1, yet Store C recovers its CAC on the first order and Store B needs about 7.5 months and a second purchase. The ratio shows how much a customer returns. Payback shows how soon. Cash-tight stores should weigh payback at least as heavily.

Work out first-order gross profit for each store. That is average order value times gross margin.

Store A earns $42 on the first order against a $70 CAC. Its second order arrives after about four months (12 months divided by 3 orders a year) and lifts cumulative profit to $84. That covers CAC.

Store B needs a second order too, but customers buy about 1.6 times a year, so the gap is closer to 7.5 months. Cumulative profit reaches $93.50 then, against a $75 CAC.

Store C never needs a repeat order to break even. Its low ratio reflects a one-purchase business, not a leak.

These are averages. Real customers do not reorder on a schedule, and some never return. Check payback by cohort before you rely on it. Our customer LTV analysis guide explains how.

The For Entrepreneurs guide makes the same cash point for SaaS. It notes that larger businesses with cheap capital can afford a longer recovery, while startups usually cannot, and that profitability turns anemic once recovery stretches past 12 months in its model. Apply that as a caution, not a rule. Your own cash position sets the real limit.

How Do You Turn LTV CAC Into a Maximum CAC?

Divide margin LTV by your target ratio.

Divide margin LTV by your target ratio to get a maximum CAC. At a 3:1 target, Store A can pay up to $84 per customer, which is its $252 margin LTV divided by 3. Store B's ceiling is $37.40 against a real CAC of $75. First-order break-even is a second, stricter ceiling: order value times gross margin.

A ceiling turns a ratio into a rule your media buyer can follow.

Break-even ROAS is 1 divided by gross margin, as our break-even ROAS calculator guide explains. It is the return you need on the first order alone.

Each store reads differently:

• Store A is under its 3:1 ceiling of $84 but over its first-order break-even of $42. Every new customer loses money on the first order and earns it back on the second. That works only if the repeat rate holds. Watch it by cohort.
• Store B is over both ceilings. At a $75 CAC, hitting 3:1 would take a margin LTV of $225, roughly double today's $112.20. Or CAC would need to fall to $37.40.
• Store C is under its first-order break-even, so it is profitable from the first sale. A 3:1 target would mean cutting CAC from $55 to $24, more than half. For a one-purchase store, first-order break-even is the better ceiling.

Choose the ceiling that matches your cash and your repeat behavior. Then hand that number to whoever buys your ads.

What Should You Fix First When LTV CAC Is Too Low?

Fix the side that is easier to move.

When the ratio is too low, work on whichever side moves fastest for your store. Store B has two paths: raise margin LTV from $112.20 to about $225 to reach 3:1 at a $75 CAC, or cut CAC to $37.40. Most stores work both sides, starting with the lever their data shows is weakest.

Match the move to the result:

• Store A: scale with care. The ratio clears 3:1. Raise spend in small steps and check the margin ratio and second-order rate after each step, since higher spend usually pushes CAC up.
• Store B: lift repeat purchases first. Its gap is on the LTV side. Replenishment reminders, post-purchase email and bundles all raise orders per customer. Our customer retention guide covers the tactics.
• Store C: protect first-order profit. It already pays for itself. Add a second-purchase offer to lift LTV, but do not chase 3:1 at the cost of the first-order margin.

On the CAC side, better ad creative and a landing page that converts more of the same clicks both lower cost per customer without cutting spend.

When Should You Distrust Your LTV CAC Number?

When the inputs are thin.

Distrust your LTV CAC number when history is short, channels are blended, or discounts skew the customer mix. With under 12 months of orders, lifespan is a guess. Shopify's guide says CLV is not a fixed number, so recalculate as cohorts age and hold your inputs constant between runs.

Three situations call for extra care.

Short history. Lifespan drives LTV. A store with five months of data is projecting, not measuring. Treat the first ratio as a starting estimate.

Blended channels. One company-wide ratio can hide a channel that loses money on every customer. Split it by channel once you have enough orders. Our LTV CAC formula guide lists this and three other mistakes that distort the result.

Discount-driven cohorts. Customers won on a steep discount may behave differently from full-price buyers. Track them separately before you average them together.

Run the numbers again each month with the same inputs and the same window. Watch CAC and LTV as two lines rather than one ratio, so you see which one moved.

Frequently Asked Questions

What is LTV CAC?

LTV CAC is the ratio of customer lifetime value to customer acquisition cost. A customer worth $300 over their lifetime who cost $100 to win gives a 3:1 ratio. Shopify names 3:1 as a good target, though the right level depends on your gross margin and how quickly you recover acquisition cost.

What is a good LTV CAC ratio for ecommerce?

Shopify says 3:1 is good and describes 3:1 to 5:1 as an efficient range, with higher ratios suggesting you may be underinvesting in growth. Treat that as a starting point. A store with 70% gross margin and repeat buyers can run differently from a one-purchase store with 50% margin.

Should I use revenue or margin in LTV CAC?

Use margin when you set a spending ceiling, because revenue ignores the cost of the product. In the worked example, Store B looks close to the line at 2.7:1 on revenue but sits at 1.5:1 on margin. Use either one consistently, and check which version any benchmark uses.

Is LTV CAC or CAC payback more important?

You need both. The ratio shows how much profit a customer returns over time, and payback shows how soon. Store C in the worked example has the weakest margin ratio, 1.3:1, yet the fastest payback, on the first order. Cash-tight stores should watch payback closely.

Keep Reading

• LTV CAC Formula: How to Calculate and Read the Ratio, the exact formula and the four mistakes that distort it.
• CAC to LTV Ratio: The Metric That Predicts Business Health, benchmarks by industry and how to fix a ratio that is underwater.
• Customer LTV Analysis: How to Segment and Act on It, how to split a blended ratio by channel and cohort.
• Break-Even ROAS Calculator, how to turn gross margin into the return your ads must hit.