Customer acquisition cost formula: how to calculate CAC for a finance business

Customer acquisition cost (CAC) is the number that tells you whether your marketing is building a business or burning money. Most guides explain it for online shops and software companies. A lender, insurer, PMS firm or fintech app needs more care, because a "customer" arrives weeks after the lead, and what that customer earns you can be paid once or spread over years.

This guide gives you the customer acquisition cost formula, shows what to include, works through an example for a finance business, and explains how to find the most you can afford to pay. For the wider picture, see our guide to digital marketing for financial services in India.

What is customer acquisition cost?

Customer acquisition cost is the average amount you spend to win one new customer.

It includes every cost of finding and converting that customer: ads, GST you can't claim back, agency fees, tools and the time your sales team spends on the leads. It does not include costs you would pay anyway, such as servicing customers you already have.

Brown Men Marketing (BMM) is a digital marketing agency for financial services. We plan every campaign backwards from CAC, from fintech marketing to lending, insurance and wealth, because CAC is the number that decides whether more ad spend is worth it.

The customer acquisition cost formula

CAC = total acquisition costs ÷ new customers won

Both numbers must come from the same period and the same campaigns. If you spent ₹1,38,000 in October and that spend produced 10 new customers, your CAC is ₹13,800.

The formula is simple. The hard parts are deciding what counts as a cost, and what counts as a customer.

Who counts as a customer in finance?

A customer is someone who earns you money, not someone who filled in a form. For most finance businesses, that means:

Counting leads, sanctions or app installs as customers makes CAC look far lower than it is. A sanctioned loan that never disburses earns nothing.

What to include in acquisition costs

Include every cost you would not have had without the campaign. For a finance business, that usually means:

• Ad spend on Google, Meta, LinkedIn, YouTube, X or ChatGPT.
• GST on ad spend. Google Ads in India adds GST at 18%, either as IGST or as CGST and SGST of 9% each, depending on your billing address (Google's GST page). If you can't claim it back as input tax credit, it is part of your cost. Your tax adviser can confirm whether you can.
• Agency or freelancer fees, if someone runs the campaigns for you.
• Tools: your CRM, WhatsApp Business platform, landing page builder or call software.
• Sales team time: the share of salaries spent calling and following up these leads.

Pick a version and keep it. Some businesses track ads-only CAC; others track fully loaded CAC with everything above. Both are useful. Switching between them from month to month makes CAC look better or worse when nothing has changed.

A worked example for a lender

The numbers below are illustrative, to show how the pieces fit together. They are not benchmarks.

A lender runs Google and Meta campaigns for business loans for one month.

On ad spend alone, CAC would look like ₹10,000. The fully loaded figure is 38% higher. If you set budgets on the ads-only number, you will overspend on every loan.

How to calculate CAC from your funnel

You can also work out CAC from the steps in between. This shows where the cost comes from.

CAC = cost per qualified lead ÷ share of qualified leads that become customers

If a qualified lead costs you ₹2,000 and 1 in 5 qualified leads becomes a customer (20%), your CAC is ₹2,000 ÷ 0.2 = ₹10,000.

This version tells you which lever to pull:

• Cost per qualified lead too high? The targeting, ad message or landing page is the problem. Our guide to CPQL, cost per lead vs cost per qualified lead covers how to measure and lower it.
• Too few qualified leads closing? The problem is after the lead: response time, the sales pitch, pricing or eligibility rules that reject people late.

It also shows why a cheap lead isn't always a cheap customer. Leads that never qualify add cost and close nothing.

Your break-even CAC: the most you can afford to pay

CAC on its own means little. ₹13,800 is cheap for one business and ruinous for another. Compare it with your break-even CAC: what one customer earns you, after costs.

How you work that out depends on how you get paid. Each line below uses illustrative numbers.

Loan DSA. You earn a payout on disbursal. On a ₹30 lakh home loan with a 0.5% payout, that is ₹15,000. If sub-agents take 20%, you keep ₹12,000. In the example above, a CAC of ₹13,800 would lose money on every loan.

NBFC or lender on its own book. Add the processing fee and the interest margin you earn over the loan, then subtract the expected loss from defaults. Your credit team will have these figures. See how we approach loan lead generation for NBFCs.

PMS or AIF. You earn a fee every year the client stays. On ₹50 lakh at a 2% annual fee, that is ₹1,00,000 a year. A client who stays four years is worth about ₹4 lakh in fees, before costs. See how we approach PMS and AIF lead generation.

Insurer or agent. You earn a first-year commission, then renewal commission each year the policy is paid. Add them over the years customers typically keep paying. More on insurance lead generation.

Fintech app. Add the revenue an active user brings over the time they stay active: interest, fees or commissions. Use active users, not installs.

If your CAC is above break-even, increasing ad spend only makes the loss bigger. Fix the funnel first. Our CAC calculator works out your break-even figure from your own numbers for each of these business types, and tells you whether ads are likely to pay back.

CAC payback period: when the money comes back

CAC payback period is how long a customer takes to earn back what you spent to win them.

Payback period = CAC ÷ what one customer earns you each month

This matters more in finance than in most industries, because businesses get paid on very different timelines:

• A DSA is paid once, soon after disbursal. Payback is quick, but you pay for ads weeks before the payout arrives.
• A PMS firm earning ₹1,00,000 a year from a client (about ₹8,300 a month) with a CAC of ₹50,000 recovers it in about six months.
• An insurer or agent may earn most of the value in renewals, so payback can take a year or more.

The longer the payback, the more cash you need to keep campaigns running before customers pay for themselves. Plan that cash before you scale.

The LTV to CAC ratio

The LTV to CAC ratio compares a customer's lifetime value (what they earn you over the whole relationship) with what they cost to win.

LTV to CAC ratio = lifetime value ÷ customer acquisition cost

A ratio of 3:1 or better is often quoted as healthy; Shopify's guide, for example, treats 3:1 to 5:1 as efficient. Treat that as a rule of thumb, not a target. A 4:1 ratio built on fees paid over six years can still squeeze your cash flow if you are growing fast.

Five mistakes that distort CAC in finance

1. Counting leads or installs as customers. CAC must use customers who earn you money.
2. Ignoring the time lag. A loan can disburse weeks after the enquiry. Match each month's spend with the customers it produced, or use a rolling three-month view.
3. Leaving out GST and sales time. Both are real costs, and together they can add a third or more to ads-only CAC.
4. Mixing in customers your ads didn't win. Referrals and walk-ins lower your average but say nothing about whether the ads work. Track paid CAC and blended CAC separately.
5. Judging channels on cost per lead. One channel can bring cheap leads and expensive customers. Compare channels on CAC.

What CAC tells you about your agency

Ask any agency, including us, to report three numbers every month: cost per lead, cost per qualified lead and customer acquisition cost. Cost per lead is the easiest to make look good. CAC is the one that shows whether the campaigns make you money.

To see what a qualified lead costs in each segment, check our CPQL Index. If you lend, our post on advertising rules for NBFCs and digital lenders covers what your ads can say.

The bottom line

The customer acquisition cost formula is total acquisition costs divided by new customers. In finance, the work is in counting the right customers, including the full cost, and comparing the result with what a customer earns you. Know your break-even CAC before you raise budgets, and judge every channel on CAC, not on cost per lead.