SaaS CAC Calculator

Many SaaS companies undercount CAC by excluding salaries, benefits, and overhead from the calculation, producing a partial-CAC number that looks healthier than it actually is. A fully-loaded CAC includes every dollar spent on sales and marketing: the full cost of sales-team salaries, commissions, bonuses, and benefits (typically 25–35% of base salary above direct comp); marketing-team salaries and benefits; commissions paid to sales and channel partners; software tools (CRM, marketing automation, sales engagement, analytics); ad spend across all paid channels; content creation (internal writer salaries, agency retainers, contractor work); event sponsorships and attendance costs; and allocated corporate overhead (portion of office, legal, accounting, management) that directly supports the GTM function. Partial CAC — counting only ad spend or only direct commissions — can be 3–5× lower than fully-loaded CAC for the same business, which produces dangerously optimistic unit economics when carried forward into LTV:CAC ratios or payback period calculations. Investors always ask for fully-loaded CAC during due diligence and will discount any number that isn't. The healthy reporting discipline is to publish fully-loaded CAC as the headline number, with a breakdown showing partial components (paid CAC, direct CAC, fully-loaded CAC) so the reader understands the composition.

The SaaS Magic Number, popularized by Scale Venture Partners, measures how efficiently sales and marketing spend converts to new recurring revenue. It's calculated as net new ARR generated this quarter divided by total sales and marketing spend in the previous quarter. The previous-quarter denominator reflects the lag between acquisition spend and the full ramp of the sales cycle — spend in Q2 produces closed-won ARR that lands mostly in Q3. A Magic Number above 1.0 means each dollar of S&M spend generates more than a dollar of new ARR annually — a strong signal to invest more aggressively in sales and marketing because the math compounds. Above 0.75 is healthy and typically signals room to scale S&M spend without damaging unit economics. Between 0.50 and 0.75 suggests a go-to-market motion that's working but not yet ready for aggressive scaling — focus on process improvements and channel optimization before adding headcount. Below 0.50 signals fundamental GTM problems — either the sales process isn't working, the ICP is wrong, the product isn't hitting the market, or the pricing doesn't support the CAC structure. Companies at sub-0.5 Magic Number should fix the underlying issue before scaling spend.

CAC payback period measures how many months of subscription revenue it takes to recoup the cost of acquiring a customer, and it's the single most important CAC efficiency metric for evaluating sustainable scaling. The formula is fully-loaded CAC divided by (monthly ARPU times gross margin), with gross margin included because recouping CAC requires covering the variable costs of serving the customer, not just hitting the gross revenue number. SaaS benchmarks by stage: pre-seed and seed companies can accept 18–24 month payback periods because they're still optimizing product-market fit and expect CAC to decline as they scale. Series A companies should target CAC payback under 15 months, with 12 months being the healthy target. Series B and beyond benchmarks tighten: under 12 months is the target and under 9 months is excellent. Public SaaS companies with strong unit economics (Atlassian, HubSpot, Veeva, Zoom at their respective stages) routinely show 6–9 month CAC payback. Payback period interacts with churn: a company with 10-month payback and 5% monthly churn only recovers CAC from about 60% of customers before they churn, making the effective payback far worse than the headline number suggests. The healthy metric pairs: CAC payback under 12 months AND LTV:CAC above 3:1 AND net revenue retention above 100%.