Blended CAC Ratio
Total fully-loaded S&M spend in the period divided by the dollars of new CARR generated in the period (new-customer + expansion CARR combined). Per the SMSB standard, the headline efficiency ratio for the full sales-and-marketing motion — answers "how many cents do we spend on S&M to add one dollar of contracted ARR." Common pitfall: blending without separately reporting New CAC Ratio and Expansion CAC Ratio hides which side of the motion is driving efficiency — for a healthy SaaS company expansion CAC is usually 3–5× cheaper per dollar than new-logo CAC. — Sales KPI anchored to SaaS Metrics Standards Board.
Rogue ID: sales.blended_cac_ratio
Type: Number
Domain: Sales
Definition
Total fully-loaded S&M spend in the period divided by the dollars of new CARR generated in the period (new-customer + expansion CARR combined). Per the SMSB standard, the headline efficiency ratio for the full sales-and-marketing motion — answers "how many cents do we spend on S&M to add one dollar of contracted ARR." Common pitfall: blending without separately reporting New CAC Ratio and Expansion CAC Ratio hides which side of the motion is driving efficiency — for a healthy SaaS company expansion CAC is usually 3–5× cheaper per dollar than new-logo CAC.
Formula
Blended CAC Ratio = Total S&M Spend (period) / (New CARR + Expansion CARR generated in period). Per SMSB §Blended CAC Ratio: spend uses the same fully-loaded definition as CAC; CARR-based denominator (not ARR) reflects committed contract value at the point of sign.Why it matters
The portfolio-level efficiency number — one ratio that summarizes the full S&M engine. Boards use it to track quarter-over-quarter efficiency improvement as the motion matures.
How to interpret
Per SMSB convention, a Blended CAC Ratio < 1.0 means the company is acquiring more contracted ARR than it spends on S&M — capital-efficient growth. 1.0–1.5 is acceptable while the motion is scaling; > 2.0 sustained signals either a motion or pricing problem. Always pair with the New and Expansion CAC Ratio split to localize the issue.
Calculation policy
How an AI agent should compute this KPI from messy company data. Free-text rules consumed at reasoning time — not a deterministic DSL. The most common ways to get this wrong are listed under Common miscomputations.
Inclusion rules
- Numerator: total fully-loaded S&M spend for the period (same definition as
sales.cac). - Denominator: total new CARR generated in the period — new-customer CARR + expansion CARR combined.
- Use CARR (contracted, including signed-not-yet-live) for the denominator, per SMSB convention — it reflects committed value at the point of sign.
Exclusion rules
- R&D / G&A / COGS from the numerator.
- Renewal CARR from the denominator — renewals are not new selling activity.
- Churn / downgrades — this is a gross-efficiency ratio, not a net one.
Required inputs
- Fully-loaded S&M spend for the period.
- New-customer CARR for the period.
- Expansion CARR for the period.
Data-source priority
- Financials for S&M spend; CRM for new + expansion CARR, same period boundary.
Edge cases
- Sales-cycle lag: same consideration as
sales.cac— for long cycles, consider lagging S&M and disclose. - A quarter with near-zero new CARR (e.g. seasonal trough) produces an enormous ratio — annualize or use a trailing window for stability, and disclose.
Validation checks
- Blended CAC Ratio should sit between New CAC Ratio and Expansion CAC Ratio — it is a weighted blend. If it falls outside that range, the spend allocation or the CARR split is wrong.
- A ratio < 1.0 means more contracted ARR added than S&M spent — capital-efficient. Sustained > 2.0 is a motion/pricing problem.
Common miscomputations
- Using ARR instead of CARR in the denominator — understates the denominator by the implementation backlog and overstates the ratio.
- Reporting only the blended number without the New / Expansion split — hides which motion is driving (or dragging) efficiency.
- Including renewal CARR in the denominator — renewals cost almost nothing and artificially deflate the ratio.
- Mixing a CARR denominator with an ARR-based New/Expansion split — the three ratios then fail to reconcile.
Related KPIs
sales.new_cac_ratiosales.expansion_cac_ratiosales.cacsales.cac_payback_periodsales.new_businesssales.expansionsales.carr
Source
SaaS Metrics Standards Board · section: Blended CAC Ratio — published 2023-01-01.
Why does this cite SaaS Metrics Standards Board? Read the ontology methodology for the published vs editorial tier system, attribution rules, and dispute process.
Metric definitions reference standards published by the SaaS Metrics Standards Board (saasmetricsboard.com). imboard is not affiliated with, endorsed by, or a member of SMSB.
Stage relevance
| Company stage | Priority |
|---|---|
| Series A | Recommended |
| Series B | Recommended |
| Series C+ | Recommended |
| Public | Recommended |
Suggested for stages: Series A, Series B, Series C+, Public.
Default owning functions
- Sales
- Finance
Machine-readable
- This KPI as JSON:
/api/ontology/sales/blended_cac_ratio.json - All Sales KPIs:
/api/ontology/sales.json - Full catalog:
/api/ontology/index.json
Average Contract Value
Average annualized contract value across new-customer deals signed during the period (ACV). Defines where the company plays on the SaaS deal-size spectrum and dictates the operating model — high-ACV businesses tolerate longer sales cycles and direct sales motions; low-ACV businesses must run product-led or inside-sales motions to keep CAC payback short. Common pitfall: blending new and expansion ACV obscures the new-logo deal-size trend that boards actually want to see. Anchored to KBCM/Sapphire SaaS Survey 2024 §Average Contract Value for cross-company benchmarking. — Sales KPI anchored to KBCM/Sapphire SaaS Survey 2024 (15th Annual).
Customer Acquisition Cost
Fully-loaded sales-and-marketing (S&M) expense incurred to acquire one new customer during the period. Per the SMSB standard, the CAC numerator includes salaries + commissions + benefits + travel + marketing programs + tooling — i.e. all S&M costs, not just direct-attribution paid acquisition. The denominator is new logos, not deals. Common pitfall: omitting fully-loaded comp (especially BDR/SDR base salary and CS-team cost-of-sale where they participate in expansion) understates CAC and inflates every downstream efficiency metric. The board cares about CAC alongside CAC Payback and the CAC Ratio family — single-number CAC is a building block, not a verdict. — Sales KPI anchored to SaaS Metrics Standards Board.