Understanding SaaS Magic Number
How we calculate. Magic number = annualized net new ARR ÷ prior S&M spend. See our methodology and accuracy policy .
Real-world scenario: A typical SaaS Magic Number case uses net new arr 250000 and prior s&m spend 400000. Enter the same figures below to reproduce the worked path.
What is SaaS Magic Number?
A sales-efficiency KPI. Distinct from Rule of 40 (growth + profit) and from finance Rule of 72.
- Net new ARR = period net new annual recurring revenue
- × 4 annualizes a quarterly net-new figure
- Prior S&M = sales & marketing spend in the prior period
The Formula
Worked Example
Common Use Cases
- Sales efficiency: hire vs hold
- Board packs: magic number trend
- Budgeting: S&M ROI proxy
Pro Tips
- State quarterly vs monthly inputs
- Don’t confuse with Rule of 40
- Freeze net-new ARR definition
| Scenario | When to use |
|---|---|
| Percent of a number | Finding a part of a whole (tax, tip, score) |
| Percent change | Comparing old vs new values |
Limitations: SaaS Magic Number results are educational SaaS / subscription planning aids—not accounting, tax, or investment advice. Confirm definitions with your billing system and board reporting standards.
Common mistakes
- Swapping part and whole: The denominator must be the full total, not a subset.
- Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
- Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.
The worked example for saas magic number was verified with the calculator form on this page—enter the same values to confirm the result.
When to use this calculator
- Use this page when your wording matches saas magic number and the form labels on screen.
- Use percent of a number for “what is X% of Y?” problems.
- Use number is what percent when you know part and whole and need the percent.
Still unsure about saas magic number? Start with the quick answer above, then open the linked calculator that matches your wording.
❓ Frequently Asked Questions
How do I use this saas magic number calculator?
For saas magic number, enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.
What formula does this page use?
See the quick answer and formula box above for saas magic number—the same percentage calculator expression is applied to your inputs.
What if my result looks wrong?
When checking saas magic number, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.
Authoritative References
For SaaS metrics and subscription performance concepts, consult:
- SaaStr — SaaS growth and metrics context
- For Entrepreneurs — SaaS metrics explainers
- Bessemer Venture Partners — cloud / SaaS industry research