Unit Economics: Is Each Customer Making You Money?

A business can grow its revenue, raise its advertising budget and take more orders every month, and still lose money. It happens when each individual sale costs more than it brings in. Unit economics is the tool that shows this early, long before the problem turns up in the annual accounts.

The method is universal. Online shops, service businesses, SaaS companies, clinics and B2B firms all use it. It belongs in the basic toolkit of every marketing manager and business owner, because it answers one simple question: is this growth actually profitable?

In this guide we cover:

• what unit economics is and what counts as a "unit";
• which models exist and how to choose between them;
• which metrics are used and how to calculate each one;
• how to calculate unit economics step by step, with a worked example in euros;
• where to get the data, which mistakes are common and how to improve the numbers.

What unit economics is

Unit economics is a method for calculating how much profit or loss a single unit brings to the business, where the unit is the smallest thing that generates revenue.

The unit is whatever makes you money: a customer, a deal, the sale of one product or one service. In other words, you are working out how much you earn on one gym membership, one pair of shoes sold in an online shop, or one business customer paying a monthly software subscription.

Once you know how much one unit brings in and how much it costs, you can make decisions that are very hard to make without those numbers:

• how much you can afford to spend to win one customer;
• how many customers, sales or deals you need to reach profit;
• what a product or service should cost so that your costs are covered;
• which advertising channels pay off and which ones only burn budget;
• whether the business can scale, or whether every bit of growth just makes the loss bigger.

The calculation depends on what you define as the unit: one customer or one sale. That choice decides which unit economics model fits your business.

Which unit economics models exist

The right model depends on the nature of the business and the kind of relationship you have with customers. The two most common are the customer model and the transaction model.

The customer model

Here you measure the profit from one customer over the whole relationship. This model suits most businesses, online and offline, that rely on long relationships and repeat purchases: a gym selling renewing memberships, an internet provider whose customers stay for years, an online coffee shop where the same person orders every month, or a software company charging a monthly subscription.

The transaction model

Here you measure the profitability of a single sale. This model suits businesses where each deal is usually a one-off: event production, custom furniture, a home renovation or building a website for a company.

Combining the two models

You can use either model on its own or combine them. A neighbourhood pharmacy, for example, works mainly on the transaction model: most people buy medicine when they need it. But for a customer with a chronic condition who buys medication regularly, the customer model fits better. It helps you understand why that customer keeps choosing this particular pharmacy: the location, the pharmacist's service or the loyalty programme.

The key metrics in unit economics

Unit economics works with a set of metrics usually written as English abbreviations: LTV, CAC, ARPU, CM and so on. There are not many core metrics, and 10 to 15 are usually enough to get the full picture. Here are the most important ones.

Users, customers and the cost of acquiring them

User Acquisition (UA) is the number of users you attracted, meaning how many people reached your website or app from your advertising. A user is not a customer yet: they arrived and saw the product, but did not buy. People who did buy are labelled Buyers or Customers (B or C).

Acquisition Cost (AC) is your total spend on attracting users in a given period: the media budget in Google Ads and Meta, and sometimes the fees you pay an agency or freelancer to run the campaigns.

Cost per user is how much it cost to attract one user: AC divided by UA. In unit economics literature this metric is sometimes called CPA (Cost per Acquisition). Be careful here: in the ad platforms, CPA usually means cost per conversion, that is, per action such as a purchase or a form submission. To avoid confusion, define clearly in your reports what you are counting. For a detailed breakdown of the differences, read our guide to CPC, CPM, CPA and CPL.

Conversion Rate (CR) is the share of users who became customers. If 20 out of 1,000 visitors bought, the conversion rate is 2%. It shows how well the whole funnel works, from the ad, through the website, to the payment page.

Customer Acquisition Cost (CAC) is the cost of winning one customer. Add up every acquisition expense, including media, external suppliers and tools, and divide by the number of new customers. For example: you spent €2,000 on ads, paid an agency €1,000 to run them, and 50 new customers bought. CAC = 3,000 / 50 = €60.

Revenue and direct costs

Average Payment Count (APC) is the average number of purchases per customer: total purchases divided by the number of customers. If 100 customers made 300 purchases, APC is 3.

Average Order Value (AOV) is total revenue for the period divided by the number of orders. If you sold 100 units at €10, 100 at €15 and 100 at €20, your average order value is €15.

Cost of Goods Sold (COGS) is the direct cost of what you sold: the supplier price of the product, packaging, shipping, card processing fees and payment platform fees. These are variable costs that only exist when a sale happens. Advertising does not go into COGS; it is counted in CAC.

1COGS covers extra costs that only apply to the first sale. Many businesses have none, but some do: a welcome gift, an onboarding call for a new software customer, or a starter kit shipped once.

Profit per customer and per user

Average Revenue per Customer (ARPC) is the average revenue from one customer after direct costs but before marketing costs:

ARPC = (AOV − COGS) × APC − 1COGS

In plain words: take the average order value, subtract the direct cost, multiply by the number of purchases per customer and subtract the first-sale costs.

Average Revenue per User (ARPU) is how much one visitor brings in on average, whether or not they buy: ARPU = ARPC × CR.

Contribution Margin (CM), sometimes called marketing gross profit, is what is left after direct costs and acquisition costs:

CM = (ARPU − cost per user) × UA

You can also calculate it per customer: CM = (ARPC − CAC) × number of customers. The result is the same, because the two formulas only differ in where the conversion step is applied. If CM is positive, every sale makes money. If it is negative, every additional sale makes the loss bigger. CM is also used to calculate your break-even point, the minimum level of sales at which the business covers all of its costs.

LTV: the value of a customer over time

Lifetime (LT) is how long a customer stays active.

LTV (Lifetime Value) is how much profit a customer brings over the whole relationship with the business, or over a defined period. There are several formulas, and you choose one based on your business model and the data you have. In the simplest version, LTV is the gross profit from a customer across all of their purchases, which is ARPC calculated over the customer's full lifetime.

For subscription businesses such as SaaS or maintenance services, it is convenient to calculate it from monthly churn: LTV = monthly revenue per customer × gross margin / monthly churn rate. For example: a customer pays €49 a month, the gross margin is 80% and 5% of customers leave each month. LTV = 49 × 0.8 / 0.05 = €784.

The LTV:CAC ratio and the payback period

Two derived metrics help you make decisions quickly:

• LTV:CAC shows how many times the profit from a customer covers the cost of acquiring them. A common rule of thumb in the startup world is a ratio of 3:1 or higher. A ratio of 1:1 or lower means the business loses money on every new customer.
• Payback Period is how many months it takes to earn back the acquisition cost: CAC divided by the monthly gross profit per customer. If CAC is €200 and a customer brings €40 of gross profit a month, payback takes 5 months. The shorter the period, the less capital you need to grow.

How to calculate unit economics: a step-by-step example

Depending on the type of unit, deal or customer, different metrics take centre stage. In the transaction model the most important figure is contribution margin (CM). In the customer model it is LTV and its ratio to CAC.

Let's take a fictional online shop selling skincare products. All the amounts below are purely illustrative and all of them exclude VAT. What matters is consistency: either everything excludes VAT, or everything includes it.

Step 1: collect the input data for the period

• Monthly advertising budget in Google Ads and Meta (AC): €5,000;
• Visitors from advertising (UA): 10,000;
• Conversion rate (CR): 2%, which means 200 new customers;
• Average order value (AOV): €60;
• Direct cost per order (COGS), including product, packaging, shipping and payment fees: €26;
• Welcome gift with the first order (1COGS): €3;
• Average number of purchases per customer in the first year (APC): 2.

Step 2: calculate the metrics

• Cost per user = 5,000 / 10,000 = €0.50;
• CAC = 5,000 / 200 = €25;
• ARPC = (60 − 26) × 2 − 3 = €65;
• ARPU = 65 × 2% = €1.30;
• CM = (1.30 − 0.50) × 10,000 = €8,000.

Step 3: interpret the result

The contribution margin from this month's campaigns is about €8,000 over the first year of these new customers. Each visitor brings in €1.30 on average and costs €0.50, and a customer who costs €25 to acquire returns €65. The advertising pays off, and if you can increase the budget without the cost per user rising much, it is worth testing.

Now let's add a €1,000 monthly fee for an agency that runs the campaigns. CAC rises to €30, and the contribution margin falls to (65 − 30) × 200 = €7,000. The picture is still positive, but it shows how much every cost line changes the final number.

Step 4: test scenarios

The real power of unit economics is in "what if" questions. What happens if the conversion rate drops to 1%? ARPU falls to €0.65, and the margin over the cost per user becomes very thin. What if the average order value rises to €70? ARPC jumps to €85. This is easy to build in Google Sheets or Excel: one row per input, one row per formula and one column per scenario.

Where to get the data

The calculation is only as good as the data that goes into it. In most businesses that information is spread across several systems:

• Ad platforms: Google Ads and Meta Ads Manager show spend, clicks and conversions per campaign;
• Google Analytics 4: visitors, traffic sources and the conversion rate on your website;
• Your shop platform or CRM: orders, average order value, repeat purchases and churned customers. You can export this data from WooCommerce, Shopify, Webflow Ecommerce or a CRM such as HubSpot or monday CRM;
• Your payment provider and accounting: processing fees, refunds and cancellations, and supplier invoices.

The hard part is joining these sources together: knowing that the customer who just made a third purchase originally came from a particular campaign. For that you need consistent UTM parameters, correctly configured conversion events and a CRM that records the lead source automatically. Keep privacy rules in mind as well: in the EU, analytics and advertising tracking generally depend on visitor consent under the GDPR and the ePrivacy rules, so your consent setup affects how complete your data is. This is general information, not legal advice. We explain how to connect all of these systems in our guide to end-to-end marketing analytics.

How unit economics works for different types of business

The principles are the same everywhere, but the emphasis shifts.

Online shop

The unit is usually an order or a customer. Calculate COGS in full: shipping, packaging, payment fees and returns. Many shops discover that free shipping above a certain order value eats a large share of the profit on smaller orders.

Service business: clinic, firm, studio

The unit is a customer or an appointment. COGS includes the professional's working time and materials. It is especially important to track the cost per lead and the share of leads that become customers, because the gap between an enquiry and a closed deal is often large.

SaaS and subscriptions

The unit is the customer. The key metrics are LTV, CAC, monthly churn and the payback period. A small improvement in churn affects LTV more than almost anything else.

B2B with a long sales cycle

The unit is a customer or a deal. CAC should include not only advertising but also sales team time, demos and events. The calculation is usually done per quarter or per year rather than per month.

Common mistakes when calculating unit economics

Not counting all acquisition costs

If you calculate CAC from the media budget alone, the picture looks better than reality. If an agency or freelancer runs the campaigns for a specific product, their fee belongs in CAC. If an in-house marketer on a fixed salary works on many projects at once, their cost goes into fixed costs rather than the CAC of one product. The important thing is to choose a rule and stick to it.

Forgetting small direct costs

Payment fees, shipping, returns, discounts and coupons look negligible on a single order, but at volume they can wipe out a large part of the profit.

Mixing prices with and without VAT

Ad platforms usually show spend excluding VAT, while the price a customer pays in your shop often includes it. If you calculate one number one way and another number the other way, every metric shifts.

Drawing conclusions from too short a period

APC and LTV need time. If you look at a single month of data, the actual number of purchases will look lower than it really is, simply because customers have not had time to come back yet.

Using one average for the whole business

Different channels, products and audiences have different unit economics. A single overall average can hide one very profitable channel and another that is losing money. Calculate per channel, and at the very least per product category.

How to improve your unit economics

Suppose your CAC is higher than ARPC, or the business is profitable but earning less than you want. There are several levers, and each one moves a different metric:

• Raise the average order value: bundles, complementary products and upselling to a premium version. Keep in mind that higher prices can lower the conversion rate;
• Lower COGS: negotiate with suppliers, use more efficient packaging, switch to a different shipping carrier;
• Increase purchases per customer: email, WhatsApp or SMS messages, a loyalty programme and reminders to reorder;
• Improve the conversion rate: a fast website, a focused landing page, a short form and a simple checkout raise ARPU without adding a single euro to the budget;
• Drop unprofitable channels: and move the budget to channels where CM is positive.

Treat every change as an experiment. Change one thing, give it time, then recalculate.

How RJL Studio helps you build a business with profitable numbers

Good unit economics starts with a website that converts and data you can trust. At RJL Studio we build websites and online shops connected to Google Analytics 4, the ad platforms' pixels and your CRM, so you can see which channel every customer came from and how much they brought in.

We run ad campaigns and social media marketing with customer acquisition cost tracking built in, and we connect your website, CRM, payment provider and email tools through automation and integrations, so the data for these calculations lands in one place without manual work.

Want to know whether your advertising is really profitable? Get in touch and we will review your funnel and your data together.

Frequently asked questions

What is the difference between unit economics and a profit and loss statement?

A profit and loss statement shows the picture for the whole business, including fixed costs such as rent and salaries. Unit economics looks at one unit, a customer or a deal, and checks whether it is profitable after direct costs and acquisition costs. A unit can be profitable while the business as a whole still loses money, if there are not enough sales to cover the fixed costs.

What is a good LTV:CAC ratio?

A common rule of thumb is 3:1 or higher: a customer brings in at least three times what it cost to acquire them. A ratio below 1 means every new customer loses money. A very high ratio can be a sign that you are investing too little in growth.

Can you calculate unit economics for a new business with no data?

Yes, as a forecast. Make assumptions about cost per click, conversion rate, average order value and direct cost, and check whether the result makes sense. After a month or two of advertising, replace the assumptions with real data and recalculate.

Should the agency fee be included in CAC?

If the agency works specifically on campaigns for the product or channel you are calculating, yes. If it is an employee on a fixed salary who handles many tasks, their cost goes into fixed costs. Choose one rule and apply it to every calculation.

How often should you recalculate unit economics?

For most businesses once a month is enough, plus whenever something major changes: a new ad channel, a price change, a new shipping provider or a product launch. When your data flows automatically into a spreadsheet or dashboard, the calculation takes minutes.