C4 · Economics & metrics · ratio

GTM Magic Number

Also: Magic Number

Definition. The Magic Number measures ARR added per dollar of Sales & Marketing spend in the prior quarter. Originally proposed by Josh James (Omniture/Domo), it is a capital efficiency diagnostic: > 0.75 signals healthy GTM ROI; > 1.0 means every S&M dollar generates more than a dollar of new ARR; < 0.5 is a warning that the GTM engine is not productive.

established Last updated 2026-06-18 Source: Josh James / Omniture (original formulation); Bessemer Venture Partners State of the Cloud 2024; Andreessen Horowitz SaaS benchmarks

Formula

GTM Magic Number ratio

Magic Number = \frac{A R R _{Q} - A R R _{Q - 1}}{S&M spend _{Q - 1}}

Plain English: Magic Number = Net New ARR (this quarter) / S&M Spend (prior quarter)

Notation: Magic_Number = (ARR_Q - ARR_{Q-1}) / S&M_spend_{Q-1}

Benchmark by stage

Source: Josh James / Omniture (original formulation); Bessemer Venture Partners State of the Cloud 2024; Andreessen Horowitz SaaS benchmarks

Stage	GTM Magic Number	Notes
Warning	< 0.5	S&M spend is not generating sufficient ARR; investigate GTM fit, CAC, or market saturation
Acceptable	0.5 – 0.75	Marginal efficiency; may be appropriate during ramp or market expansion investment
Good	0.75 – 1.0	Healthy GTM ROI; standard benchmark for efficient SaaS
Excellent	> 1.0	Each S&M dollar generates > $1 of ARR; green light for growth investment
Exceptional	> 1.5	Rare; often driven by PLG, strong brand moat, or network effects

Naive vs corrected

Version	Formula
Naive	Net new ARR / current quarter S&M spend (no lag — mismatches spend timing with pipeline generation; sales cycles mean current S&M generates future ARR, not current)
Corrected	Use prior quarter S&M spend as denominator to align spend with the ARR it actually generated. For long sales cycles (> 6 months), lag by the average sales cycle length. Use annualized net new ARR when comparing across different deal sizes.

Common errors

Using current quarter S&M spend (no lag) — mismatches timing of investment and output
Excluding CSM costs that are part of the expansion motion from the S&M denominator
Interpreting a high Magic Number as a green light without checking gross margin or payback period
Not adjusting for one-time large deals that inflate a single quarter's net new ARR
Using MRR rather than ARR — produces a metric that is 12× smaller and harder to benchmark

Where this sits

Part of the Economics & metrics (C4) cluster in the GTM World Model. Related to the model's "Magic Number > 1.0 implies CAC payback < 12 months at 100% gross margin; at 75% gross margin, Magic Number > 1.0 implies payback < 16 months; relationship: Payback_months ≈ 12 / (Magic_Number × GM%)" equation.

cac →cac payback →burn multiple →rule of 40 →

How to cite this

@misc{shalvi_gtm_metric_magic_number_2026,
  author = {Singh, Shalvi},
  title  = {GTM Magic Number — GTM World Model Metrics},
  year   = {2026},
  url    = {https://shalvisingh.com/gtm/metrics/magic-number}
}

Singh, Shalvi. "GTM Magic Number — GTM World Model Metrics." shalvisingh.com, 2026. https://shalvisingh.com/gtm/metrics/magic-number