Magic Number
A sales efficiency metric that measures how much new ARR is generated for every dollar spent on sales and marketing. Calculated as net new ARR divided by prior-period S&M spend.
The Metric That Tells You Whether to Press the Gas
The magic number is the quickest way to know if scaling sales and marketing spend will create value or destroy it. It strips away all the noise — pipeline metrics, lead quality debates, attribution arguments — and asks one question: for every dollar you spent, how much recurring revenue did you create?
How to Calculate It
Magic Number = (Current Quarter ARR - Previous Quarter ARR) / Previous Quarter S&M Spend
Use ARR, not MRR. Use total sales and marketing spend, fully loaded. The lag between spend and revenue is intentional — it takes time for marketing to convert.
What to Do With the Number
| Magic Number | Interpretation | Action |
|---|---|---|
| Above 1.0 | Highly efficient | Scale aggressively |
| 0.75 - 1.0 | Efficient | Invest more, optimize |
| 0.5 - 0.75 | Borderline | Fix before scaling |
| Below 0.5 | Inefficient | Stop, diagnose, fix |
The Limitation Nobody Mentions
The magic number has a one-quarter lag built in. That means it penalizes companies that just ramped a new sales team or launched a major campaign. If you hired 5 AEs last quarter, your S&M spend spiked but their pipeline has not closed yet. Look at 2-quarter rolling averages for a fairer picture.
Frequently Asked Questions
How do you calculate the SaaS magic number?
Take the increase in ARR from one quarter to the next, then divide by the previous quarter's total sales and marketing spend. If ARR grew by $500K and you spent $400K on S&M last quarter, your magic number is 1.25. Above 0.75 is generally considered efficient enough to invest in growth.
What is a good magic number?
Above 0.75 means you should invest more in sales and marketing. Between 0.5 and 0.75 means your GTM is working but needs optimization. Below 0.5 means something is broken — your conversion rates, positioning, or target market needs work before you scale spend.
