A negative ceiling means the required retained contribution already exceeds the sale contribution. Repeat revenue is excluded.
Try this with your own numbersFormula and worked example
Maximum spend per lead = (revenue − delivery cost − retained contribution) × close rate
| Input | Example |
|---|---|
| First-sale revenue | 800 |
| Variable delivery cost | 500 |
| Contribution to retain | 100 |
| Qualified lead close rate | 25 % |
| Calculated result | 50 per qualified lead |
Choose reliable inputs
Account for delivery time, review work and when you expect to be paid for each engagement. For this accounting practice calculation, use time sheets, engagement scopes and invoice ageing and a consistent definition of one engagement.
- Professional hours: include the portion belonging to this engagement or reporting period, and record where the value came from.
- Software: include the portion belonging to this engagement or reporting period, and record where the value came from.
- Review: include the portion belonging to this engagement or reporting period, and record where the value came from.
Use the same currency for every money input. Do not mix weekly costs with monthly revenue, or count the same expense in both an itemised cost and allocated overhead.
What can I afford to pay for a lead?
A negative ceiling means the required retained contribution already exceeds the sale contribution. Repeat revenue is excluded.
What if this input changes?
If first-sale revenue rises by 10%, this example changes by 20 per qualified lead. This shows the effect of one change; it does not predict what will happen.
Open the calculator, save your baseline, then change the input supported by the least reliable estimate in your records. Compare both scenarios before committing to a price or capacity promise.