How to measure B2B lead generation ROI (without kidding yourself)
Every agency deck shows a screenshot of pipeline. Almost none show CAC payback. That's not an accident — the pipeline number is easy to inflate and the payback number is hard to fake. Here are the three formulas that actually measure the engine.
CAC payback tells you if the engine pays for itself. Pipeline coverage tells you if you'll hit the quarter. Blended ROAS tells you which channel to grow. Use all three; each one alone lies.
CAC payback — the honest number
Formula: (monthly cost of the lead gen engine) ÷ (net-new gross profit per month). If the answer is under 12 months, the engine is paying for itself. Above 18 and something's off — usually ACV, close rate or list quality.
Pipeline coverage — the forecasting number
Formula: open pipeline ÷ remaining quarter target. Below 3x you probably won't hit; above 5x you're either sandbagging or your close rate is broken.
Blended ROAS — the allocation number
Formula: closed-won attributable revenue ÷ total lead gen spend (people + tools + agency + ads). Break it down by channel monthly. The channel with the highest ROAS gets the next €1 of budget — not the channel with the loudest advocate on the team.
Three traps that make ROI reports lie
- Counting sourced pipeline instead of closed-won. Sourced is a top-of-funnel vanity number. Only closed-won pays salaries.
- Excluding the internal cost. If a rep spends 8 hours/week on follow-up, that's part of CAC.
- Attributing first-touch only. B2B buyers touch 6-9 sources. First-touch overweights ads; last-touch overweights outbound. Blend them or you'll cut the wrong channel.