SaaS Magic Number

The SaaS Magic Number measures how efficiently your sales and marketing spend converts into new recurring revenue. The common formula divides the net new ARR added in a period by the sales-and-marketing spend of the prior period: net new ARR / prior-quarter S&M. Roughly, a result above 0.75 means each dollar of go-to-market is producing enough new ARR to pay itself back inside about a year - a green light to spend more. Between 0.5 and 0.75 is workable but worth optimizing; below 0.5 signals your acquisition engine is inefficient and pouring in more budget will just burn cash. The metric is useful precisely because it forces the growth question into ROI terms rather than raw pipeline. Caveats: it's noisy for early-stage companies with lumpy deals, it ignores expansion timing, and it says nothing about retention - a high magic number with high churn is a leaky bucket. Use it alongside payback period and net revenue retention, not on its own.