Compare with the contribution remaining after delivering the sale. Revenue alone overstates the amount available for rewards.
Try this with your own numbersFormula and worked example
Retained contribution = revenue × contribution margin − reward − program cost
| Input | Example |
|---|---|
| First-sale revenue | 800 |
| Contribution margin | 40 % |
| Referral reward | 75 |
| Program cost per sale | 25 |
| Calculated result | 220 per referred sale |
Choose reliable inputs
Include software licences, delivery time, revisions and ongoing support when costing a project. For this it support calculation, use project time logs, licence invoices and retainer scopes and a consistent definition of one support ticket.
- Technician time: include the portion belonging to this support ticket or reporting period, and record where the value came from.
- Software: include the portion belonging to this support ticket or reporting period, and record where the value came from.
- Escalation work: include the portion belonging to this support ticket 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 rewards be compared with revenue or contribution?
Compare with the contribution remaining after delivering the sale. Revenue alone overstates the amount available for rewards.
Excludes lifetime repeat purchases and any tax treatment of rewards.
What if this input changes?
If first-sale revenue rises by 10%, this example changes by 32 per referred sale. 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.