Two stores each pay SAR 80 to win a new customer through ads. The first sells a product bought once; the second sells something customers come back for every two months. On the first order the two stores may look identical — and the ad may even look unprofitable for both. But after a year, the second store has made six times as much profit from the same customer.
That difference is what two core e-commerce concepts measure: customer lifetime value (LTV) and customer acquisition cost (CAC). Understanding how they relate changes how you judge ads, how much you can pay to win a customer, and where you invest your effort.
What is customer lifetime value (LTV)?
It’s the total a customer brings your business over the whole relationship. In its simple form:
Revenue LTV = average order value × orders per year × years a customer stays
But revenue doesn’t pay for ads — profit does. So the more accurate version is:
Profit LTV = revenue LTV × gross margin
Example: average order SAR 250, the customer buys 3 times a year, stays about two years, and margin is 40%. Revenue LTV = SAR 1,500; profit LTV = SAR 600.
What is customer acquisition cost (CAC)?
CAC = total marketing and sales costs over a period ÷ new customers in the same period
If you spend SAR 20,000 on marketing in a month and gain 250 new customers, CAC is SAR 80. Watch two points:
- New customers only: don’t divide by all orders, because repeat orders from existing customers aren’t new acquisition.
- All the costs: ads, influencers, marketing tools, and part of marketing salaries if you can. Counting ads alone gives a CAC lower than reality.
The LTV:CAC ratio
It’s the profit of the customer relationship compared with the cost of winning it. In the example: 600 ÷ 80 = 7.5 : 1 — every riyal spent winning the customer returns seven and a half riyals of gross profit over the relationship.
| Ratio | General reading |
|---|---|
| Below 1 : 1 | Each new customer costs more than they return; growth means bigger losses |
| 1 : 1 to 3 : 1 | Profitable, but may not cover fixed costs and growth |
| 3 : 1 or more | A common rule of thumb treats this as healthy |
| Far above 5 : 1 | May mean you’re under-investing in growth |
3:1 is a widely used rule of thumb, not a law. A business with heavy fixed costs needs a higher ratio; one with cash and a goal of fast growth may accept a lower ratio for a while. Our LTV:CAC calculator works out the ratio, net customer profit after CAC, and the maximum CAC that keeps a 3:1 ratio.
CAC payback: when does your money come back?
The ratio alone isn’t enough, because profit arrives in stages. A customer who will generate SAR 600 of profit over two years doesn’t hand it to you today. Payback tells you when you recover the cost of winning them:
Orders to pay back = CAC ÷ profit per order
In the example: profit per order is SAR 100 and CAC is 80, so the first order alone covers the cost. But if CAC were SAR 250, you’d need 2.5 orders — about 10 months at 3 orders a year. During those months you’re funding your store’s growth out of pocket, which matters a great deal for cash flow.
A practical rule: if cash is tight, make sure the first or second order covers acquisition cost. If you have solid data on repeat purchases and enough cash, you can pay a CAC above first-order profit because you know the customer will come back.
Why this changes how you judge ads
Judging a campaign by first-order ROAS alone suits products bought once. For repeat products — fragrance, skincare, coffee, supplements, children’s clothing — a campaign that looks break-even or slightly negative on the first order may be one of your most profitable over the year.
The reverse is also true: a campaign that brings profitable first orders from deal-hunters who never return may be worth less than it looks. That’s why it helps to compare customer value by acquisition source, by tracking campaigns with UTM links and linking orders to customers in your store.
How to raise customer lifetime value
LTV has three levers — order value, purchase frequency and lifespan — plus the margin that multiplies them all.
- Raise order value: bundles, complementary products on product and cart pages, and a free-shipping threshold.
- Raise frequency: replenishment reminders for consumables, subscriptions, and offers for existing customers only.
- Extend lifespan: an excellent delivery experience, fast customer service on WhatsApp, and a fair return policy that builds trust.
- Raise margin: every margin point lifts profit LTV directly; review your costs with our profit margin calculator.
And how to lower CAC
- Improve store conversion rate, so the same traffic yields more customers.
- Better ads that raise click-through and lower the cost per visit.
- Cheaper channels: organic content, SEO and referrals from existing customers.
- Referral programmes: a happy customer often brings new ones more cheaply than ads.
Common calculation mistakes
- Using revenue LTV instead of profit, which makes the ratio look far better than it is.
- An optimistic lifespan estimate without data; start conservative and update.
- Calculating CAC from ads only while ignoring other marketing costs.
- Mixing new and repeat customers when calculating CAC.
- One average for every customer: customer value varies a lot by first product and channel; segment once your data grows.
An example: two channels with different acquisition costs
A skincare store wins customers from two channels. The figures are illustrative:
| Hard-offer ads | Specialist influencer content | |
|---|---|---|
| CAC | SAR 60 | SAR 110 |
| Orders per customer per year | 1.5 | 4 |
| Profit LTV (two years, SAR 80 profit per order) | SAR 240 | SAR 640 |
| LTV:CAC | 4 : 1 | 5.8 : 1 |
The first channel looks cheaper in the ads dashboard, but customers from the second come back far more often, so they end up more profitable despite costing almost twice as much. Without LTV, the obvious move would be to cut the pricier channel — the wrong call here.
Key takeaways
- Calculate LTV on gross profit, not revenue.
- CAC = all marketing costs ÷ new customers only.
- 3:1 is a rule of thumb for a healthy ratio, not a fixed law.
- Watch payback period, because it determines cash pressure.
- For repeat products, judge campaigns by customer value, not the first order alone.
Frequently asked questions
My store is new and I don’t know my repeat rate. What should I do?
Start with a conservative estimate (one or two orders a year) and judge ads on first-order profit at first. After six months of data, calculate your real frequency and update the numbers.
Does LTV matter for products bought once?
Less, but not zero: a happy customer may buy another product or recommend you. In that case focus on first-order profit and break-even.
How often should I calculate these numbers?
Roughly every quarter, and after any big change in pricing, channels or products.
A customer isn’t one order, and an ad isn’t a one-off transaction. Calculate your customers’ value and acquisition cost with our free LTV:CAC calculator — and if you want a growth strategy that combines acquisition and retention, get in touch.
