SaaS magic number calculator

Magic Number = (Q current ARR − Q prior ARR) × 4 ÷ S&M spend in prior quarter. A "magic number" greater than 1 means every $1 of sales-and-marketing investment generates $1 of new ARR in the same year.

Magic Number
0.00
Net new ARR (quarter)
$0
Annualised new ARR
$0
QoQ growth
0%
CAC payback (months)

How to interpret

  • < 0.5: sales engine is broken — fix before adding more reps.
  • 0.5–0.75: growth costs more than $1.30 per $1 ARR — slow it.
  • 0.75–1.0: proceed with caution; CAC payback > 12 months.
  • > 1.0: healthy — invest more in S&M.
  • > 1.5: exceptional — you’re likely under-investing in growth.

Pair this with CAC / LTV and Rule of 40 to triangulate sales efficiency.