Definition
SaaS Magic Number definition: a sales efficiency heuristic that compares net new ARR to prior-period sales & marketing spend (with a lag).
Formula
Magic Number ~ (net new ARR in quarter * 4) / prior-quarter sales & marketing spend
Example
If net new ARR in the quarter is $1.0M and prior-quarter sales & marketing spend was $2.0M, Magic Number ~ ($1.0M * 4) / $2.0M = 2.0.
How to use it
- Use a consistent lag (often one quarter) so trends are comparable.
- Pair with retention or burn multiple to validate quality of growth.
Common mistakes
- Ignoring lag effects between spend and revenue.
- Using blended averages that hide channel differences.
Measured as
Magic Number ~ (net new ARR in quarter * 4) / prior-quarter sales & marketing spend
Misused when
- Ignoring lag effects between spend and revenue.
- Using blended averages that hide channel differences.
Operator takeaway
- Use a consistent lag (often one quarter) so trends are comparable.
- Pair with retention or burn multiple to validate quality of growth.
- Keep SaaS Magic Number consistent by cohort, segment, and period before you use it as a decision signal in planning or reporting.
- Interpret the metric alongside retention, margin, or payback so one ratio does not hide the real operating trade-off.
Next decision
- Quantify the impact with SaaS Magic Number Calculator: Formula, Benchmark, and Example if you need to turn the definition into an operating assumption.
- Read SaaS Magic Number: definition, formula, and how to use it if the decision depends on interpretation, policy, or trade-offs beyond the raw formula.
Where to use this on MetricKit
Calculators
- SaaS Magic Number Calculator: Formula, Benchmark, and Example: Calculate SaaS Magic Number using net new ARR and prior-period sales and marketing spend, with formula, benchmark ranges, and example.
Guides
- SaaS Magic Number: definition, formula, and how to use it: SaaS Magic Number definition explained: what it measures, the formula, an example, lag assumptions, and how to interpret it alongside burn multiple and payback.
- Burn multiple: definition, formula, and how to use it: Burn multiple explained: net burn / net new ARR. Learn how to compute it, interpret it, and avoid common mistakes.