You will be able to calculate customer acquisition cost for the business and for each channel you can track.
Priya was pleased with her Meta ads. Each lead, a parent who filled in the trial class form through an ad, cost her about S$20. Her Google ads cost about S$60 a lead. On those numbers, Meta was three times better value, and she was ready to move money across. Then she checked how many of those leads had actually enrolled.
The answer changed the picture, and the reason it changed is the subject of this lesson: what one new customer really costs, counted honestly.
Customer acquisition cost, often shortened to CAC, is what you spend to win new customers in a period, divided by the number of new customers you won in that period. If you spent S$3,000 in a quarter and won 15 new customers, your acquisition cost was S$200 per customer.
The idea is simple. The hard parts are deciding what counts as spend, which customers count as new, and which period they belong to. Make those decisions once, write them down, and use the same ones every time, so that this quarter's figure can be compared with last quarter's.
New customers means first-time buyers, not repeat orders from existing ones. For Priya, it is newly enrolled students. For Farah's workwear shop, it is customers placing their first order. Your source of truth from lesson 5.2 is where you count them.
The most common mistake is to divide ad spend alone by new customers. That gives a flattering number, because ads are rarely the whole cost of winning a customer.
Count everything you spend on marketing and sales in the period. Ad spend, yes. Also the tools: email software, a scheduling app, a design subscription, the booking system if its cost is mainly about winning customers. Freelancers and agencies, such as a designer who makes ad graphics or an agency that runs campaigns. And a fair share of staff time spent on marketing and sales, including your own.
Staff time is the item people leave out, and for a small business it is often one of the biggest. Estimate the hours honestly and put a rate on them, even a rough one, and label it clearly as an estimate.
Here is Priya's quarter, with example figures:
Google Ads: S$1,800 Meta ads: S$900 Tools, including email and booking software: S$300 A freelance designer for flyers and ad graphics: S$600 Her own time on marketing, an estimated 30 hours at S$40 an hour: S$1,200
Total: S$4,800. She enrolled 24 new students in the quarter. Her blended acquisition cost was S$4,800 divided by 24, or S$200 per student. Using ad spend alone, S$2,700 divided by 24, she would have said S$112.50. The honest figure is nearly 80 percent higher.
Write down what you left out as well as what you included. Priya left out the rent for the centre, since she would pay it with or without marketing, and noted that decision on the sheet.
The figure above is blended: all costs, all new customers, all channels together. It is the most reliable acquisition cost you can calculate, because it does not depend on deciding which channel deserves credit for which customer. Every dollar and every customer is counted once.
Acquisition cost by channel is more useful for decisions and less reliable. To say that Google Ads customers cost S$200 each, you need to know how many customers Google Ads produced, which means relying on attribution, with all the blind spots from module 5. Platform numbers overclaim, GA4 misses people who decline cookies or switch devices, and word of mouth shows up nowhere.
So calculate blended acquisition cost first and treat it as the anchor. Then calculate per-channel figures as a second view, using your best attribution evidence: GA4, your self-reported source question from lesson 5.3, and the platforms' own numbers for comparison. If the channel figures add up to something very different from the blended one, the attribution is the likely culprit.
Now back to Priya's leads. Her S$900 of Meta ads produced 45 trial form leads at S$20 each. Her S$1,800 of Google Ads produced 30 leads at S$60 each. But when she matched leads to enrolments in her spreadsheet, Meta's 45 leads had produced 3 new students, and Google's 30 had produced 9.
Per student, using ad spend only, Meta cost S$900 divided by 3, or S$300, and Google cost S$1,800 divided by 9, or S$200. The channel with cheap leads was the more expensive way to win a student. Many of the Meta leads were parents browsing on their phones who never answered her follow-up message; the Google leads were parents who had searched for maths tuition in Tampines and were ready to book.
Cost per click and cost per lead are useful inside a platform, for comparing ads and audiences. They are poor guides for moving money between channels, because cheap clicks and cheap leads can come from people who rarely buy. The number that decides where money goes is cost per customer, ideally checked against what those customers are worth, which is the subject of lesson 8.2.
When you work out your own figure, expect it to be higher than any number you have quoted before. A higher, honest figure is more useful than a low one that leaves out half the costs.
Calculate last quarter's blended customer acquisition cost for your business, listing every cost you included and every one you left out.
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