Business
Subscription Box Unit Economics Calculator
Calculate paid boxes, collected revenue, variable cost and contribution per box, operating profit, CAC, churn-implied lifetime, contribution LTV, LTV-to-CAC ratio, and monthly break-even boxes.
Expected paid and fulfilled boxes-
Expected collected subscription revenue-
Variable cost per paid box-
Contribution per paid box-
Monthly box contribution-
Operating profit after overhead and acquisition-
Customer acquisition cost (CAC)-
Expected customer lifetime from churn-
Contribution lifetime value (LTV)-
Contribution LTV to CAC ratio-
Paid boxes required for monthly break-even-
Decision view
Subscriber cohort decay and per-box contribution stack
Subscriber cohort decay and per-box contribution stackA live retention curve follows the entered churn while the box stack separates product, fulfillment, postage, payment fee, and contribution.
Exact scenario comparisonMonthly subscriber churn (%) changes while all other entered assumptions remain constant.
| Monthly subscriber churn (%) | Expected paid and fulfilled boxes | Expected collected subscription revenue | Variable cost per paid box | Contribution per paid box | Monthly box contribution | Operating profit after overhead and acquisition | Customer acquisition cost (CAC) | Expected customer lifetime from churn | Contribution lifetime value (LTV) | Contribution LTV to CAC ratio | Paid boxes required for monthly break-even |
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How to use Subscription Box Unit Economics Calculator
- Enter active billed subscribers, price, refund or failed-payment rate, and each per-box cost.
- Add fixed overhead, acquisition spend, and new subscribers to calculate operating profit and CAC.
- Enter monthly churn to inspect cohort decay, expected lifetime, contribution LTV, and LTV-to-CAC.
Calculator guide
Understanding Subscription Box Unit Economics Calculator
Subscription economics joins two different systems: contribution on the current box and survival of a customer cohort. A strong margin today can still produce weak acquisition economics when churn shortens the paying lifetime.
Detailed calculation process
Detailed subscription-box unit-economics calculation
The default month bills 1,800 subscribers at $42 with a 4% refund and failed-payment rate.
General formula: B_p=B(1-z)v=c_p+c_f+c_s+pfCM=p-vP=B_p*CM-H-ACAC=A/Nlife=1/hLTV=CM/h Only paid boxes create collected revenue. Contribution is calculated before period overhead, while churn converts one-box contribution into a simple customer lifetime value.
What each symbol means
Worked substitution with the default inputs
The default month is slightly unprofitable despite a 5.93 contribution LTV-to-CAC ratio, demonstrating why current-period and cohort views must remain separate.
Worked situations
Practical examples
- The default 1,800 billed subscribers at a 4% loss rate produce 1,728 paid boxes.
- Each $42 box contributes $14.232 before overhead and acquisition; 8% churn implies 12.5 months of simple expected lifetime.
Better inputs
Useful tips
- Measure churn on the same monthly starting-customer basis used by the model.
- Include fulfillment and postage actually incurred for refunded boxes if they still ship.
- Compare cohort-level realized contribution with this steady-state planning model.
Before relying on the result
Limitations and common mistakes
- The reciprocal-churn lifetime assumes a constant geometric retention process.
- Reactivation, annual plans, cohort aging, discounts, expansion revenue, inventory waste, and refund timing are excluded.
- CAC includes only the entered acquisition spend and new customers.
Reference
Key terms
- Contribution per box
- Collected price less product, fulfillment, postage, and payment fee.
- Churn
- Share of subscribers lost during a month.
- CAC
- Acquisition spend divided by newly acquired subscribers.
- Contribution LTV
- Contribution per box multiplied by simple churn-implied lifetime.
Important note
Use contribution LTV consistently: do not compare a gross-margin LTV with a fully loaded CAC or vice versa without stating the bases.
Frequently asked questions
Why divide 100 by churn percentage?
For a constant monthly geometric churn process, 1/churn is the simple expected number of paid periods.
Is a high LTV-to-CAC ratio enough?
No. Cash timing, payback period, overhead, fulfillment capacity, and retention uncertainty also matter.
Why is acquisition spend deducted from operating profit?
The default page treats it as a current-month operating investment while also using it to calculate CAC.