SaaS CAC Payback & Magic Number

Two sales efficiency metrics every SaaS board should track: CAC Payback (months to recover S&M cost via gross margin) and Magic Number (new ARR generated per dollar of S&M spend). Together they answer: is your sales engine efficient enough to scale? Best-in-class SaaS has payback under 12 months and Magic Number above 1.0.

Magic Number Formula and Tiers

Magic Number = (New ARR ÷ Prior-Quarter S&M). Above 1.0: Press the gas — every dollar of S&M generates more than $1 of new ARR. Invest more, scale aggressively. 0.75-1.0: Optimize, don't scale yet. Focus on conversion improvements. 0.5-0.75: Slow down. Find what's broken in your funnel. Below 0.5: Stop adding sales reps until efficiency improves.

CAC Payback Period Calculation

CAC Payback = (CAC ÷ ARPA per month × gross margin). For aggregate calculation: Quarterly S&M ÷ (New ARR × gross margin ÷ 12). Best-in-class SaaS: under 12 months. Healthy: 12-18 months. Concerning: 18-24 months. Crisis: 24+ months. Salesforce maintained ~15 months payback at scale. Snowflake achieves under 12 months through usage-based pricing accelerating revenue. The gross margin assumption matters — 75% is standard for SaaS, but lower (50-65%) for infrastructure SaaS with heavy AWS bills.

Diagnostic Patterns

Pattern 1: High Magic Number (>1) but high payback (>18 months) = pricing is right but contribution margin too low. Raise prices or improve gross margin (reduce AWS, optimize support cost). Pattern 2: Low Magic Number, low payback = small deals close fast but you're not generating enough volume. Need more leads or higher conversion. Pattern 3: Low Magic Number, long payback = both problems. Pause hiring sales reps. Improve efficiency first, then scale. Source: OpenView Partners benchmarks, SaaStr, Bessemer.

Last updated May 2026. Sources: OpenView.