What is a good CAC payback period for SaaS?
Payback is the number that tells you how much you can afford to spend. It is also the one most often calculated wrong.
- How long should CAC payback be?
- Is 18 months too long?
- Do we use revenue or gross margin?
A common target for B2B SaaS is to recover customer acquisition cost (CAC) within 12 months, and David Skok's SaaS Metrics guide notes the best companies do it in about 5 to 7 months. Longer payback can be fine with high retention, strong funding and large contracts, but it ties up cash. Always calculate payback on gross margin, not revenue, or you will overstate how fast you earn the money back.
The formula
CAC payback in months = sales and marketing cost to win a customer, divided by (monthly recurring revenue per customer × gross margin). Include salaries, ads, tools and agencies in CAC, not just ad spend.
| Input | Value |
|---|---|
| Sales and marketing spend this quarter | $300,000 |
| New customers won | 50 |
| CAC | $6,000 |
| Monthly revenue per customer | $800 |
| Gross margin | 80% |
| Payback | $6,000 ÷ ($800 × 0.8) = 9.4 months |
What changes the target
High net revenue retention lets you accept longer payback, because customers grow after they sign. Bootstrapped companies usually need shorter payback because cash is tight. Enterprise deals often run longer because sales cycles are long and contracts large. We set a target per segment rather than one number for the company.
Common mistakes
Leaving salaries out of CAC, using revenue instead of gross margin, and blending very different segments so a bad channel hides behind a good one.
- CAC that counts only ad spend.
- Payback on revenue instead of gross margin.
- One blended number across very different segments.
- Ignoring churn when payback is long.
- Scaling a channel before its payback is measured.
- Fully loaded CAC including people and tools.
- Payback by segment and channel.
- Gross margin in the formula.
- A target agreed with finance before spend increases.
- Payback reviewed quarterly as costs change.
What founders and researchers say
We read the threads, surveys and reports so you don't have to. Each card is our summary, linked to the source.
Skok's guideline: the best SaaS companies recover CAC in about 5 to 7 months, and profitability gets weak beyond 12. He calls these guidelines, not rules.
Read the guide →The median private B2B SaaS company spends about 23% of ARR on sales and marketing combined. Payback tells you whether that spend is working.
Read the benchmarks →SaaS threads often show founders calculating payback on revenue or leaving salaries out. The most upvoted corrections add both back in.
Browse the threads →Community summaries describe recurring themes across many threads. They are not quotes from individual posts.
Read next
Go deeper in the ShoutEx guides, or check the original sources.
Bring your numbers. We'll tell you what we would do, even if it isn't us.
Book a call →Follow-up questions
Is 18 months CAC payback bad?
It can be acceptable with strong retention, large contracts and funding. It is risky for bootstrapped companies or with high churn.
Should CAC include the founder's time?
If the founder sells, include an estimate. Otherwise CAC looks lower than it will be once you hire.
How is payback different from LTV to CAC?
Payback measures speed of cash recovery. LTV to CAC measures total return over the customer lifetime.