With the illustrative inputs below, the result is 1,500 per month.
Try this with your own numbersFormula and worked example
Net change = leads × (new close rate − old close rate) × contribution − extra cost
| Input | Example |
|---|---|
| Qualified leads per month | 100 |
| Current close rate | 20 % |
| Scenario close rate | 25 % |
| Contribution per sale | 400 |
| Extra monthly follow-up cost | 500 |
| Calculated result | 1,500 per month |
Choose reliable inputs
Include software licences, delivery time, revisions and ongoing support when costing a project. For this managed it service calculation, use project time logs, licence invoices and retainer scopes and a consistent definition of one client month.
- Licenses: include the portion belonging to this client month or reporting period, and record where the value came from.
- Support labour: include the portion belonging to this client month or reporting period, and record where the value came from.
- Monitoring: include the portion belonging to this client month 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.
Should I use percentage points or percentage growth?
Moving from 20% to 25% is a five percentage-point improvement. Apply the difference in rates to the same lead count.
Rate improvement must be measured or explicitly treated as a scenario.
What if this input changes?
If qualified leads per month rises by 10%, this example changes by 200 per month. 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.