How to Use This Tool
Subscription revenue can look predictable while cash disappears into products, packing, postage, replacements and payment fees every month. Contribution per box removes those variable costs from the subscription price. Multiply that amount by active shipments, then subtract fixed overhead to estimate monthly operating profit.
Churn changes what CAC is affordable
At a constant eight percent monthly churn, the simple expected lifetime is about 12.5 months. Multiplying monthly contribution by that lifetime gives a planning value before acquisition cost. This is a simplified steady-state model, not a cohort forecast: annual plans, pauses, win-backs and churn changing with tenure need cohort data.
Use contribution, not gross margin, for decisions
Gross margin often ignores fulfilment, processor and replacement costs that rise with each shipment. Contribution includes them. Compare CAC payback with cash reserves and churn: a positive lifetime estimate can still be dangerous when the business runs out of cash before payback.
Sources & assumptions
Tool Spec v2 · verified 2026-08-18. Platform rules and fees can change; the editable inputs remain authoritative for your account.
Official references
- Stripe Docs — subscription analytics and churn (checked 2026-08-18)
Model assumptions
- Monthly churn is treated as a constant probability, making expected customer lifetime approximately one divided by churn.
- Contribution excludes fixed monthly overhead; operating profit subtracts that overhead after multiplying by active boxes.
