Free tool
Affiliate commission calculator
Model what a recurring commission structure actually costs as referred customers renew and churn — monthly spend, cohort lifetime cost, and year-one totals.
Commissions modeled per paid invoice; churn shrinks the earning base each month — matching how billing-native tools actually accrue.
This month
Referred revenue
$1,600
Commissions owed
$400
One cohort, 12 months
$4,082
Total commission spend on this month’s referrals as they renew and churn out (~12.0 effective paying months).
Year 1 total
$40,409
All twelve monthly cohorts at this pace, each decaying at your churn rate.
Compare that year-one figure to what a % -of-commission platform would take on top — typically another 20–30% of these payouts — and you’ve found your software budget for the decade.
How the math works
Each month’s referred customers form a cohort earning customers × ARPU × rate in month one. In later months the cohort shrinks by your churn rate, so commission spend decays with it — exactly how billing-native affiliate tools accrue from paid invoices rather than signup events.
The year-one figure stacks all twelve cohorts. Use it two ways: as the budget line when you set your commission rate, and as the number to beat when a platform quotes you a percentage-of-commission fee — that fee lands on top of these payouts, every month, forever.
A good next step
When the math works, run it on rails
Sentalong accrues commissions from real invoice events, reverses refunds automatically, and pays affiliates monthly via Stripe — flat pricing, no cut of commissions.