C4 · Economics & metrics · ratio
Customer Acquisition Cost
Also: CAC
Definition. CAC is the fully-loaded cost to acquire one new customer: total Sales & Marketing expenditure (including headcount, tools, events, and allocated overhead) divided by new customers acquired in the same period. Industry norms vary widely by motion — PLG CAC averages under $1,000 while enterprise CAC commonly exceeds $50,000.
Formula
Customer Acquisition Cost ratio
Plain English: CAC = Total Sales & Marketing spend / New customers acquired in the period
Notation: CAC = (S&M_opex + allocated_overhead) / new_customers_acquired
Benchmark by stage
Source: OpenView SaaS Benchmarks 2024; Bessemer Venture Partners Cloud 100 data 2024; KeyBanc Capital Markets SaaS Survey 2024
| Stage | Customer Acquisition Cost | Notes |
|---|---|---|
| PLG / Self-serve | < $1,000 | Product is primary acquisition channel; CAC dominated by marketing and infra |
| Mid-market (inside sales) | $5,000–$50,000 | SDR + AE motion; CAC payback 12–18 months is acceptable |
| Enterprise (field sales) | $50,000–$500,000 | Long cycles (6–18 months); CAC must be offset by high ACV and expansion |
| Best-in-class (any motion) | LTV:CAC > 3:1 | The ratio matters more than the absolute; see ltv-cac-ratio |
Naive vs corrected
| Version | Formula |
|---|---|
| Naive | Direct S&M spend only (excludes AE salaries, SE time, marketing ops, events overhead — understates true CAC by 30–60%) |
| Corrected | Fully-loaded CAC includes: AE + SDR + CSM (acquisition portion) salaries + benefits + equity, marketing spend, tools, events, travel, allocated G&A overhead, and recruitment costs |
Common errors
- Excluding sales headcount costs from CAC (only counting ad spend)
- Using gross customer count including free trials and freemium users as the denominator
- Blending new logo CAC with expansion-only motions, which masks true acquisition efficiency
- Not lagging S&M spend by the average sales cycle length (creates denominator timing mismatch)
- Ignoring partner, reseller, or channel commissions in the numerator
Where this sits
Part of the Economics & metrics (C4) cluster in the GTM World Model. Related to the model's "Blended CAC = S&M_spend_t / new_logos_t; New-logo CAC (lagged) = S&M_spend_{t - avg_sales_cycle} / new_logos_t" equation.
How to cite this
@misc{shalvi_gtm_metric_cac_2026,
author = {Singh, Shalvi},
title = {Customer Acquisition Cost — GTM World Model Metrics},
year = {2026},
url = {https://shalvisingh.com/gtm/metrics/cac}
} Singh, Shalvi. "Customer Acquisition Cost — GTM World Model Metrics." shalvisingh.com, 2026. https://shalvisingh.com/gtm/metrics/cac