CAC (Customer acquisition cost)

Worked example (made-up numbers)

You spend $300 on Reddit ads in September. The ads bring 40 signups, and 3 of those people start paying. Your CAC for Reddit in September is $300 ÷ 3 = $100.

The same month, a post in a community costs you nothing but an evening and brings 2 paying customers. Its money CAC is $0, which is why you also count your time when you compare channels.

Why it matters when you’re starting out

Money is short, and every channel competes for the same few hundred dollars and the same evenings. CAC turns “Reddit seems to work” into a number you can compare: Reddit costs $100 a customer, the newsletter sponsorship $250, the community post an evening. On its own, CAC tells you what a customer costs; next to LTV, it tells you whether you can afford it.

How to measure it

1. Record what you spent on each channel, per month, from the invoice rather than the platform’s estimate.
2. Tag every link you put in that channel with UTM parameters, so each visit and signup carries the channel.
3. Count the paying customers each channel brought, not signups or clicks. That needs the source of each customer’s first visit matched to your payments.
4. Divide spend by paying customers, channel by channel.

Mistakes to avoid

• Dividing by signups. That’s cost per signup, a different number. Signups that never pay make it look cheap.
• One blended number. A single CAC across all channels hides the expensive one inside the cheap one.
• Tiny samples. With two customers from a channel, the next one can halve or double the number. Treat it as a first sign.

In Nordva Launch

Record what a channel cost in the dashboard or by telling your AI agent, and the Insights sources table shows cost per signup and cost per paying customer next to each source, from the customers it traced back to that source. Channel costs need the Indie plan.