Accounting practice Referral Incentive Economics
Retained contribution = revenue × contribution margin − reward − program cost
Gather time sheets, engagement scopes and invoice ageing. Include professional hours, software, and review. The starting figures are examples. Replace them with your own records.
Formula 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
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.
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.