Business
Customer Acquisition Cost Calculator
Divide acquisition spend by new customers won in the same period.
What does a customer cost to win?
Customer acquisition cost (CAC) is what you spend to win one customer. Include ads, tools and sales cost that belong to acquisition for the period, then divide by new customers won. A high CAC is fine if lifetime value is higher and payback is tolerable — compare with LTV to CAC and customer lifetime value. Blended CAC mixes organic and paid; paid-only CAC is stricter for media decisions. Free trials should count customers at a clear conversion event so CAC matches revenue reality. Agency fees and sales commissions belong in the numerator if they exist to win new logos. Set campaign floors with break-even ROAS when you think in revenue ratios. Estimates for planning only — not accounting advice. Segment CAC by channel monthly while you scale; blended figures hide a single inefficient campaign. Agree whether reactivated customers count as new before the divisor argument starts. Segment CAC by channel monthly while you scale; blended figures hide a single inefficient campaign. Agree whether reactivated customers count as new before the divisor argument starts. When agency retainers span brand and performance, allocate only the acquisition share into CAC so organic storytelling spend does not inflate the cost to win a customer.
Worked example
In a month you spend £8,000 on media, £1,200 on acquisition tools and £2,800 on sales commission tied to new logos — £12,000 total. You win 150 new customers. CAC = £80. If simple LTV is £260, LTV:CAC is 3.25:1; if payback needs more than a year of cash you cannot fund, fix retention before scaling spend.
Limits and assumptions
Attribution windows disagree between platforms and finance. Multi-touch journeys are flattened. Reactivations of churned customers may need a separate bucket from true new CAC.
Frequently asked questions
What costs belong in CAC?
Media spend, acquisition tools, sales commissions and agency fees tied to winning new customers in the period.
Should I include organic customers in the divisor?
For blended CAC, yes. For paid CAC, divide paid spend by customers attributed to paid channels.
How do free trials affect CAC?
Count customers when they convert (or define a clear trial-to-paid rule) so CAC matches revenue reality.
Do brand campaigns belong in CAC?
If you include them, be consistent and expect a higher blended CAC; some teams keep brand in a separate budget.
How often should I recalculate?
Monthly is common while scaling. Recalculate after pricing, creative or channel mix changes.