CAC Calculator
Free CAC calculator: divide sales and marketing spend by new customers won to get customer acquisition cost, plus CAC payback months when you add ARPU.
All-in for the period: ads, tools, salaries, commissions, content.
Customers won in the same period.
Optional - enables the payback calculation. Enter 0 to skip.
Used to compute payback on gross profit, not raw revenue.
Results
Customer acquisition cost
$1,250
- CAC paybackMonths of gross profit (80% margin on $150 ARPU) to recover CAC.
- 10.4 months
At $1,250 CAC and $120 of monthly gross profit per customer, you recover acquisition cost in 10.4 months - inside the under-12-months range commonly targeted for SMB SaaS.
Free and instant - nothing is stored or sent. Estimates for planning purposes, not accounting, tax, or investment advice.
Customer acquisition cost is the all-in price of winning one new customer: every dollar of sales and marketing spend in a period, divided by the customers that period produced. It is the denominator of growth - the number that decides whether spending more on acquisition builds a business or burns one.
This calculator returns CAC from two inputs, and if you add average revenue per customer (ARPU) and gross margin, it also computes CAC payback: how many months of gross profit it takes to earn the acquisition cost back.
What CAC measures - and what to include
CAC = total sales and marketing spend ÷ new customers acquired in the same period. The honest version is fully loaded: ad spend, marketing tools, content costs, and the salaries and commissions of everyone in sales and marketing - not just the ad budget.
With the defaults - $50,000 of spend producing 40 customers - CAC is $1,250. Blended CAC (all spend ÷ all new customers) is the health metric; channel-level CAC is the optimization metric. Track both.
CAC payback: the number that protects your cash
CAC payback = CAC ÷ monthly gross profit per customer, where monthly gross profit is ARPU × gross margin. At $1,250 CAC and $120 of monthly gross profit ($150 ARPU at 80% margin), payback is 10.4 months.
Payback matters because CAC is paid in cash today while the revenue arrives over months. A payback under 12 months is commonly targeted for SMB-focused SaaS; enterprise businesses tolerate longer paybacks because contracts are larger and churn is lower.
How to interpret the result
CAC in isolation says little - a $1,250 CAC is excellent for a customer worth $5,000 and fatal for one worth $800. Always read it against LTV (the related calculator) and payback.
Rising CAC over time is the metric to watch: it usually means the cheapest channels are saturating. Falling payback while CAC holds steady is the best pattern - it means pricing, margin, or expansion revenue is improving.
Frequently asked questions
What costs should be included in CAC?
Everything spent to acquire customers: advertising, marketing software, agencies, content production, events, plus the fully loaded salaries and commissions of sales and marketing staff. Excluding salaries produces a flattering number that will mislead pricing and fundraising decisions.
What is a good CAC?
Only relative to customer value. Two commonly cited screens: lifetime value at least 3× CAC, and CAC paid back by gross profit within about 12 months. A "cheap" CAC with terrible retention fails both tests; an expensive CAC on a high-value customer can pass easily.
What is the difference between blended and paid CAC?
Blended CAC divides all acquisition spend by all new customers, including organic ones. Paid CAC divides paid-channel spend by customers those channels produced. Blended looks better but can hide deteriorating paid efficiency - investors typically ask for both.
Why compute CAC payback on gross profit instead of revenue?
Because only gross profit repays acquisition cost - the COGS portion of revenue goes to delivering the service. Revenue-based payback flatters the number, and the flattery grows with lower margins. At 80% margin the difference is modest; at 40% it is enormous.
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