SaaS Magic Number, CAC Payback & Rule of 40 Calculator
Calculate SaaS enterprise sales efficiency (Magic Number), gross-margin-adjusted CAC payback period in months, and Rule of 40 growth-profitability score.
Quarterly Financial Performance
$
$
$
Total Sales & Marketing GAAP expenses in Q-1.
%
Essential for true gross-margin-adjusted CAC payback.
Growth & Cash Flow (Rule of 40)
%
%
Or non-GAAP operating margin % if FCF is unavailable.
Executive SaaS Benchmarks
OUTSTANDING EFFICIENCY (> 1.0)
SaaS Magic Number
1.60
Scale sales aggressively
CAC Payback (Gross-Margin Adjusted)
10.0 months
Tier 1 benchmark (< 12 mo)
Rule of 40 Score
50.0%
45% growth + 5% FCF
Net New ARR Generated
$2,000,000
($500k rev delta × 4)
Venture Capital Benchmarks
Magic Number > 1.0:
Pour gas on fire (scale GTM)
Magic Number 0.75 – 1.0:
Healthy SaaS efficiency
Magic Number < 0.50:
Warning: Fix churn & pipeline
Rule of 40 Status:
Passes Rule of 40 (≥ 40%)
Methodology & Definitions
Scale VP Standard
The SaaS Magic Number equals (Current Quarter Revenue minus Prior Quarter Revenue) multiplied by 4, divided by Prior Quarter Sales & Marketing spend. True CAC Payback period must adjust for subscription gross margin, calculated as 12 divided by (Magic Number × Gross Margin %).