Blended CAC Ratio

What it measures

The fully loaded sales-and-marketing spend (rep and marketer salaries, commissions, ad spend, events, content, GTM tooling) divided by the annualized value of the recurring revenue it won — both new-logo and expansion — in the same period. It tells you how many S&M dollars you deploy to add one dollar of new annual subscription run-rate from any source. It is a pure efficiency ratio of acquisition cost to total revenue growth — not a payback or lifetime-value measure on its own — and its defining trait is that it credits expansion revenue, unlike the new-logo-only CAC Ratio.

Why it matters

Blended CAC Ratio answers the question every operator must ask: are we spending efficiently to grow recurring revenue from every motion we fund? Boards use it to judge whether the combined go-to-market engine — new acquisition plus account expansion — is scaling productively per revenue dollar; you use it to sense-check whether total S&M spend is justified by the total ARR it produces. Because it folds expansion into the denominator, it captures the reality that the same sales team and marketing programs often drive both new logos and upsells — and it rewards the efficient land-and-expand motions that new-logo-only ratios ignore.

How to read it

Lower is better, but read it as a trend, never a single snapshot. A ratio of 0.5 means each acquisition dollar adds two dollars of annual revenue; a ratio of 1.5 means each dollar adds only sixty-seven cents. A rising ratio usually means CAC is climbing (higher brand spend, competitive pressure, market saturation) or revenue per dollar of spend is shrinking (mix shift to smaller logos, pricing pressure, weaker expansion). The critical discipline is to always read it next to the unblended CAC Ratio: if blended looks healthy but new-logo CAC Ratio is poor, expansion is carrying the engine and your new-customer acquisition is quietly inefficient. A business heavy on expansion will post a low blended ratio even when new-logo economics are mediocre, so segment by motion before you celebrate. Track quarter over quarter against plan to catch the moment the engine starts to strain.

What good looks like

Watch-outs

• Ignoring the mix shift between new and expansion. A flat blended ratio can hide a company losing efficiency on new logos while gaining on expansion, or the reverse — the blend masks which motion drives the value. Always compute the unblended CAC Ratio alongside it and segment the two motions.
• Using bookings or TCV instead of annualized ARR. If you put cash received upfront or full multi-year contract value in the denominator, the ratio becomes a function of billing cycles and contract length rather than acquisition efficiency — annualize to run-rate, or the ratio reads artificially low and the payback math breaks.
• Crediting expansion that the S&M pool didn't drive. If account expansion comes from product-led usage growth or contractual price escalators rather than sales-and-marketing effort, folding it into the denominator flatters the ratio. Count only the expansion your S&M spend actually worked to produce.
• Misaligning spend timing with the revenue it produced. A campaign running in Q3 may close new and expansion deals in Q4 — match S&M spend to the cohort it produced or use a rolling 12-month window, or the ratio is noisy and misleading.

Worked example