SaaS Magic Number Calculator
The SaaS Magic Number measures sales efficiency by comparing revenue growth to sales and marketing spend. It indicates how much new ARR you generate for each dollar invested in sales and marketing. This metric helps determine when to accelerate or optimize spending.
How to Calculate
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Magic Number = (Current Quarter ARR - Previous Quarter ARR) / Previous Quarter S&M Spend
Example:
Q2 ARR: $2,000,000
Q1 ARR: $1,500,000
Q1 S&M Spend: $400,000
Magic Number = ($2M - $1.5M) / $400K = 1.25
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Industry Benchmarks
| Magic Number | Efficiency | Recommendation |
|---|---|---|
| <0.5 | Inefficient | Optimize before spending more |
| 0.5-0.75 | Developing | Improve efficiency |
| 0.75-1.0 | Good | Ready to scale |
| >1.0 | Excellent | Accelerate investment |
Interpreting Your Results
A magic number above 0.75 indicates efficient growth and signals you should invest more in sales and marketing. Below 0.5 suggests you need to fix your sales engine before scaling spend.
Why This Metric Matters
Understanding SaaS Magic Number helps you:
- Make data-driven business decisions with confidence
- Benchmark against industry standards and competitors
- Identify areas for improvement in your business model
- Communicate performance clearly to stakeholders and investors
- Set realistic goals and track progress over time
Best Practices for Accurate Measurement
1. Use consistent time periods: Compare month-over-month or quarter-over-quarter consistently 2. Include all relevant data: Ensure you capture all revenue sources and costs 3. Track cohorts separately: Analyze metrics by customer segment and acquisition date 4. Monitor trends: Single snapshots are less valuable than trends over time 5. Automate tracking: Use analytics tools to ensure consistent, accurate measurement
Every Metric From These Inputs
100 customers at $49 with 3% monthly churn and $200 CAC:
| Metric | Value | Formula |
|---|---|---|
| MRR | $4,900 | customers × ARPU |
| ARR | $58,800 | MRR × 12 |
| Annual churn | 30.6% | 1 − (1 − monthly)¹² |
| Average lifetime | 33.3 months | 1 ÷ monthly churn |
| LTV | $1,633 | ARPU ÷ monthly churn |
| LTV : CAC | 8.2:1 | LTV ÷ CAC |
| CAC payback | 4.1 months | CAC ÷ ARPU |
What Good Looks Like
| Metric | Healthy | Concerning |
|---|---|---|
| Monthly churn (SMB) | Under 3% | Above 5% |
| Monthly churn (enterprise) | Under 1% | Above 2% |
| LTV : CAC | 3:1 or better | Below 1:1 |
| CAC payback | Under 12 months | Above 18 |
| Net revenue retention | Above 100% | Below 90% |
The Metric This Set Omits
Net revenue retention — expansion revenue minus churn and contraction, from existing customers only. Above 100% means the business grows without acquiring anyone, which is the single strongest signal in SaaS and the one that most affects valuation. It cannot be derived from the inputs above because it needs upgrade and downgrade data.