CAC Calculator
Blended customer acquisition cost and payback period — the two numbers that tell you whether growth is compounding or just burning cash.
Your numbers
Include ad spend, tools, and S&M salaries for a true blended CAC.
Used to compute payback in gross-profit terms, not raw revenue.
Blended CAC
$500
per new customer
CAC payback period
5.6 months
Excellent — cash-efficient growth
Rule of thumb used by most SaaS operators and investors: under 12 months to recover CAC in gross profit is considered capital-efficient; 12–18 is workable if you have runway; beyond 18 months you're essentially lending your customers money to acquire them.
Most CAC numbers are quietly wrong
The most common CAC mistake isn't the math — it's the inputs. Teams calculate CAC using only paid media spend and leave out sales salaries, content production, tools, and agency retainers. That produces a CAC that flatters the marketing team and understates what it actually costs the business to land a customer. Blended CAC — total S&M spend divided by total new customers, no matter the channel — is the number that should show up in board decks, because it's the number that shows up in cash flow.
CAC on its own doesn't mean anything
A $500 CAC is fine if customers generate $2,000/year in gross profit and terrible if they generate $200. CAC only becomes decision-useful next to LTV and payback period. Use the LTV:CAC ratio calculator to check the ratio, not just the raw cost.
Frequently asked questions
How do you calculate CAC?
CAC = total sales and marketing spend ÷ number of new customers acquired in that period. Blended CAC includes every acquisition channel — paid, organic, referral, sales salaries — and is the number that reflects reality. A 'paid CAC' that only counts ad spend will always look better than it is.
What counts as sales and marketing spend?
Ad spend, content and SEO costs, sales team salaries and commissions, marketing tools and software, agency fees, and events. Leaving out salaries is the most common way founders understate CAC.
What is CAC payback period?
The number of months it takes to recover your CAC from a customer's gross profit contribution. Formula: CAC ÷ (monthly revenue per customer × gross margin). It answers 'how long is my cash tied up in this customer before they start paying for themselves?'
What's a good CAC payback period?
There's no universal number, but a widely used operator/investor rule of thumb: under 12 months is capital-efficient, 12–18 is workable with runway, beyond 18–24 months you're financing growth rather than compounding it. Capital-intensive businesses (hardware, marketplaces with heavy supply-side subsidies) routinely run longer paybacks by design.
Should I use blended CAC or paid-channel CAC?
Use blended CAC for board reporting and unit economics decisions — it's what your P&L actually feels. Use channel-level CAC (Google Ads CAC, Meta CAC) for budget allocation decisions between channels. They answer different questions; neither replaces the other.
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LTV:CAC Ratio Calculator
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Incrementality Calculator
Test vs. control, with significance
New to the terms? See CAC, payback period, and unit economics in the marketing glossary.