What Can You Actually Afford to Pay for a Lead?
Updated
You can afford to pay, at most, your average job's profit contribution multiplied by your close rate, minus the reserve you choose to keep per lead — and running that calculation helps compare acquisition cost with the contribution expected from a lead. The calculation is straightforward once you have the three real inputs.
Where Can This Calculation Go Wrong?
The common mistake is comparing cost-per-lead across channels without ever asking what a lead is actually worth. For illustration, assume a $40 lead closes at 35% and a $12 lead closes at 4%. Compare acquisition cost with expected contribution, not lead price alone. Cost per lead means nothing without close rate and job value attached to it.
What's the Actual Formula?
Acquisition-cost ceiling per lead = (average contribution dollars per job × lead-to-job close rate) − chosen reserve dollars per lead. Contribution margin is revenue minus the direct cost of doing that job — materials, labor, subcontractors — not your full overhead-loaded number. Close rate is the real percentage of leads that become paying jobs, not the percentage of quotes you send that get accepted.
Can You Walk Through an Illustrative Example?
| Input | Assumed or Calculated Value |
|---|---|
| Average job revenue | $2,400 |
| Direct job cost | $1,500 |
| Contribution margin | $900 |
| Lead-to-close rate | 15% |
| Expected value per lead | $135 |
| Assumed reserve (40% of expected contribution per lead) | $54 |
| Max affordable cost per lead | $81 |
With these assumptions, a $60 acquisition cost per lead leaves more than the chosen reserve. At $95, $135 − $95 leaves $40, below the assumed $54 reserve. The $81 ceiling preserves the assumed 40% reserve; it does not establish net profit after overhead.
What Input Mistake Should You Avoid?
Using revenue instead of contribution margin. Use contribution after direct costs, not total revenue, when calculating this ceiling.
How Does Close Rate Change This Number Month to Month?
Close rate isn't fixed. A slower response time, a change in the sales team, or a shift in lead quality from a new channel can move your real close rate meaningfully within a quarter. Recalculating this number quarterly, not once and forgetting it, is what keeps ad spend decisions grounded in current reality instead of a number from six months ago.
How Do You Use This Number to Actually Decide Where to Spend?
Once you know your ceiling, compare it against the real, tracked cost per lead of each channel — not the platform's reported cost, your actual tracked cost including any agency fee. Use the ceiling as one input when deciding whether to change spend, alongside capacity, lead quality, cash flow and uncertainty in the assumptions. Our growth work starts with exactly this calculation before recommending where a single dollar goes.