What is customer acquisition cost (CAC)?
Customer acquisition cost is what you spend, on average, to win one new paying customer. It’s the cost side of unit economics: on its own it tells you little, but next to what a customer is worth (LTV) it tells you whether growth makes money or burns it.
The useful version is fully loaded: every cost whose job is to bring in customers, divided by the customers it brought in. For a small SaaS that’s usually ad spend, the share of salaries and contractors working on marketing and sales, and the tools they use.
CAC formula
CAC = (Ad spend + Marketing costs + Sales costs) ÷ New customersPaid-only CAC = Ad spend ÷ New customersCAC payback = CAC ÷ (Monthly revenue per customer × Gross margin)What to include in CAC
| Include | Usually exclude | Why |
|---|---|---|
| Ad spend (search, social, sponsorships) | Product engineering | Builds the product, not the pipeline |
| Marketing and sales salaries, contractors | Customer support for existing users | Retention cost, not acquisition |
| Marketing tools, content production, events | Hosting and infrastructure | Belongs in gross margin |
| Sales commissions, affiliate payouts | Refunds | Belongs in revenue, not cost |
Worked example
- Last quarter a SaaS spent $6,000 on ads, $9,000 on marketing (a part-time content contractor and tools) and $3,000 on sales (founder-led demos, a CRM, commissions): $18,000 in total.
- It won 60 new paying customers. Fully loaded CAC = $18,000 ÷ 60 = $300.
- Looking at ads alone gives $6,000 ÷ 60 = $100 — a third of the real cost.
- Customers pay $79 a month at an 80% gross margin, so each contributes $63.20 of gross profit a month. CAC payback = $300 ÷ $63.20 ≈ 4.7 months.
A payback under five months means each customer returns its acquisition cost well within its first year, so growth can largely fund itself. If the same company had a $1,000 CAC, payback would be about 16 months — viable, but cash would be tied up for over a year per customer.
What is a good CAC? Benchmarks
An absolute “good CAC” doesn’t exist — a $300 CAC is excellent for a $79-a-month product and ruinous for a $9 one. The benchmarks that hold across companies are ratios:
| Benchmark | Guideline | Source |
|---|---|---|
| CAC payback, SMB-focused | Under 12 months | Bessemer Venture Partners, “Scaling to $100 Million”, 2021 |
| CAC payback, mid-market | Under 18 months | Bessemer, 2021 |
| CAC payback, enterprise | Under 24 months | Bessemer, 2021 |
| CAC payback, best SaaS businesses | 5–7 months; beyond 12 months profitability gets “anemic” | David Skok, SaaS Metrics 2.0 |
| LTV:CAC | Above 3:1 | David Skok, SaaS Metrics 2.0 |
Common CAC mistakes
- Leaving out people costs. For most early-stage companies salaries are the largest acquisition cost. Ads-only CAC makes paid channels look cheaper than everything else.
- Ignoring the lag between spend and customers. If trials take 30 days to convert, this month’s customers came from last month’s spend. Use a quarter, or shift spend by your typical time to convert.
- Dividing by signups. Free signups and trials aren’t customers; CAC is per paying customer.
- Only looking at blended CAC. A $300 blend can hide a $90 organic channel and a $900 paid one. Split spend and customers by channel.
- Counting customers who refunded or churned in the first month. They cost the same to acquire but paid back nothing — keep them in the cost, out of the customer count, or track early churn separately.
How to measure CAC by channel with VisitTrack
The hard part of CAC isn’t the spend — that’s in your accounting — it’s knowing which channel each customer came from. VisitTrack attributes signups and payments to the referrer, campaign and landing page of the visit that earned them.
- Tag paid links with UTM parameters (the UTM builder makes them) so each campaign is identifiable.
- Track signups with
window.visitrack("signup")(custom events) — the Signups tab shows the source of every signup. - Connect your payment provider (revenue attribution) to see paying customers and revenue by source and campaign on the Revenue tab.
- Divide each channel’s spend by its paying customers for CAC per channel, then pull the same numbers monthly via the API or MCP server.
Frequently asked questions
How do you calculate customer acquisition cost?
Add up all sales and marketing spend for a period — ads, salaries, contractors, tools — and divide it by the number of new paying customers won in that period. $18,000 of spend and 60 new customers gives a CAC of $300.
What should be included in CAC?
Include everything whose purpose is acquiring customers: ad spend, marketing and sales salaries and contractors, commissions, affiliate payouts, and marketing and sales tools. Exclude product development, hosting, and support for existing customers.
What is a good CAC payback period?
Under 12 months is the common benchmark for SaaS selling to small businesses; Bessemer Venture Partners suggests under 18 months for mid-market and under 24 for enterprise. David Skok notes the best SaaS businesses recover CAC in 5–7 months.
What is the difference between blended CAC and paid CAC?
Blended CAC divides all acquisition spend by all new customers, including those from organic and word of mouth. Paid CAC divides only paid-channel spend by customers from paid channels. Blended looks better as organic grows; paid shows whether advertising itself pays off.
How is CAC payback calculated?
Divide CAC by the monthly gross profit from one customer: CAC ÷ (monthly revenue per customer × gross margin). A $300 CAC with $79 a month at 80% margin pays back in $300 ÷ $63.20 ≈ 4.7 months.
How do I lower my customer acquisition cost?
Shift spend toward channels that bring paying customers more cheaply, improve conversion on the pages those visitors land on, and shorten the path from signup to payment. You need CAC per channel first — which requires attributing customers to the channel that brought them.
Related tools and guides
- LTV calculatorWhat a customer is worth — and LTV:CAC.
- ROAS calculatorReturn and break-even for paid campaigns.
- Churn rate calculatorThe input that decides LTV.
- UTM builderTag campaigns so customers can be attributed.
- Revenue attribution (glossary)Which channel each payment came from.
- Revenue attribution docsRevenue by source and campaign, cookie-free.
Stop calculating by hand — measure it automatically
VisitTrack tracks visitors, goals, funnels and revenue from Stripe, Paddle, Polar, Lemon Squeezy and Razorpay, so these numbers are always on your dashboard. Cookie-free, one script tag, 14 days free.