How do I calculate customer acquisition cost for inbound leads that require SDR qualification before sales engagement?
Quick Answer: Calculate CAC for inbound leads that require SDR qualification by including every cost needed to turn a raw lead into a sales-qualified opportunity and then into a closed customer. In practice, that means allocating marketing spend, SDR labor, sales labor, tooling, and any overhead tied to qualification and handoff, then dividing the total by the number of new customers acquired from that inbound cohort. If you want a qualification-stage metric, also calculate Cost per SQL separately so you can isolate SDR efficiency from full-funnel CAC.
Detailed Explanation
For inbound-led revenue motions, true customer acquisition cost should not stop at the form fill or MQL stage, because SDR qualification is part of the acquisition process and directly affects conversion economics. The cleanest approach is to define the full cost stack for the cohort: media and content spend that generated the leads, SDR compensation and benefits for qualification activity, sales compensation and benefits for opportunity management, relevant software and automation costs, and an allocated share of overhead such as management and RevOps. Then attribute those costs over the number of closed-won customers from that same inbound source and time window. If your goal is operational visibility, pair full CAC with stage-specific metrics like cost per lead, cost per qualified lead, and cost per SQL so you can see where the funnel is leaking and whether SDR qualification is adding leverage or just adding expense.
Key Technical Drivers
- Define the acquisition boundary: include all costs from inbound demand generation through SDR qualification, sales engagement, and closed-won conversion for the same cohort and period.
- Use a fully loaded cost model: marketing spend + SDR compensation/benefits + sales compensation/benefits + tooling + allocated overhead, then divide by closed customers, not just qualified leads.
- Track stage metrics separately: CPL, cost per MQL, cost per SQL, and CAC by source so you can isolate whether SDR qualification improves conversion efficiency enough to justify its cost.