CAC Calculator Widget
Add a customer acquisition cost calculator to your growth content. Sales and marketing spend divided by new customers gives CAC; with monthly ARPA and gross margin it also shows how many months a new customer takes to pay that cost back.
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Under the widget on your page: Powered by A2Z Tools
Embed code
<iframe src="https://a2z.tools/embed/w/cac-calculator" title="CAC Calculator by A2Z Tools" width="100%" height="480" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>
A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.
<div data-a2z-widget="cac-calculator" data-height="480"></div> <script async src="https://a2z.tools/embed.js"></script>
Adds a small script (what it does) that sizes the widget to fit its content, loads it lazily and keeps it isolated from your page's CSS.
Works with
How it works
Blended CAC is all sales and marketing expense in a period divided by the new customers won in that same period. Include salaries and commissions of sales and marketing staff, paid media, events, content, tools and agency fees - not just ad spend, which gives a flattering paid CAC. Spending 50,000 to win 40 customers is a CAC of 1,250. Payback asks how long a customer's monthly gross profit takes to repay that: CAC / (ARPA x gross margin), the months-to-recover-CAC formula from David Skok's SaaS metrics. At 150 a month and 80% margin each customer contributes 120 a month, so payback is 1,250 / 120 = 10.4 months - inside Skok's 12-month guideline. Bessemer's benchmarks are more lenient for larger deals: under 12 months for small-business products, 18 for mid-market and 24 for enterprise. ARPA and margin are optional; with either missing the widget shows CAC alone. Zero new customers is refused, since CAC would be undefined.
Calculation method
- CAC = sales and marketing spend in the period / new customers acquired in the period
- Monthly gross profit per customer = ARPA x gross margin %
- CAC payback (months) = CAC / (ARPA x gross margin %)
Worked examples
Self-serve SaaS
Inputs: Spend 50,000; 40 new customers; ARPA 150; gross margin 80%
Result: CAC 1,250; payback 10.4 months; 120 gross profit a month per customer
Inside the common 12-month guideline.
Sales-led product
Inputs: Spend 120,000; 60 new customers; ARPA 100; gross margin 50%
Result: CAC 2,000; payback 40 months
Over three years to recover - pricing, margin or sales efficiency needs work.
An illustration of standard metric definitions, not financial advice.
Limitations
- Payback ignores churn during the payback months, so the real recovery is slower when churn is high.
- One period's figures can be distorted by a big campaign or a seasonal spike; average several months.
- Does not split CAC by channel or segment.
Where publishers use it
- Performance-marketing agency blogs explaining fully loaded acquisition cost
- Startup finance templates for board reporting
- Sales-team compensation planning articles
- Ecommerce subscription brands comparing channels
- Fundraising guides on the metrics investors ask for at Series A
Questions
What should be included in sales and marketing spend?
Everything spent to win new customers: salaries, bonuses and commissions of sales and marketing staff, advertising, events, content production, sales tools and agency fees. Excluding salaries can understate CAC by half or more in sales-led companies.
What is a good CAC payback period?
David Skok suggests recovering CAC within 12 months. Bessemer's benchmarks are about 12 months for small-business SaaS, 18 for mid-market and 24 for enterprise, where contracts are larger and churn lower.
Blended or paid CAC?
Blended CAC divides all acquisition spend by all new customers, including organic and referral sign-ups. Paid CAC divides paid-channel spend by customers from paid channels only. Blended is the honest company-level figure; paid helps compare channels.
Should spend and customers come from the same month?
Ideally offset by the sales cycle. If deals take 3 months to close, compare this quarter's customers with last quarter's spend. For short cycles, the same period is fine.
Why does payback use gross margin?
Because the customer's revenue also has to cover hosting, support and payment costs before it can repay acquisition. 150 a month at 80% margin repays 120 a month, so a 1,250 CAC takes 10.4 months, not 8.3.
Sources
- SaaS Metrics 2.0 - Detailed Definitions - David Skok, For Entrepreneurs (Matrix Partners) . CAC = sales and marketing expenses / new customers acquired; months to recover CAC = CAC / (ARPA x GM%). Checked 2026-10-01.
- Scaling to $100 Million - Bessemer Venture Partners (Atlas) . CAC payback benchmarks: SMB under 12 months, mid-market under 18, enterprise under 24. Checked 2026-10-01.
Cite or recommend this tool
If you reference this tool in an article, course or documentation, these formats are ready to copy. They are optional - nothing is added to your site unless you paste it.
A2Z Tools CAC Calculator https://a2z.tools/embed/cac-calculator
<a href="https://a2z.tools/embed/cac-calculator">A2Z Tools CAC Calculator</a>
[A2Z Tools CAC Calculator](https://a2z.tools/embed/cac-calculator)
CAC Calculator by A2Z Tools - https://a2z.tools/embed/cac-calculator
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