How do you calculate subscription app payback?
Model cumulative net subscription revenue per acquired user using billing, trial conversion, renewal, refund and commission assumptions. Payback is the first modeled charge at which that revenue covers CPA, using the same acquisition denominator. TruthPane calculates this scenario locally; model payback is not platform settlement or money arriving in a bank account.
- What you need: Billing cycle, price, trial assumptions, renewal rates, refunds, commission, model horizon and CPA.
- What you get: Modeled cumulative revenue, payback within the selected horizon and a conditional CPA ceiling.
- Limits: Future renewals are assumptions; the model does not verify taxes, operating costs or bank payout timing.
A subscription payback model asks when cumulative modeled net revenue per acquired user covers the cost of acquiring that user. The answer depends on the billing schedule and the assumptions you enter. It is not a schedule of platform settlement or bank deposits.
Define the acquired user before entering CPA
Keep the revenue and cost denominators consistent. If acquisition cost is measured per trial starter, model revenue per trial starter, including the chance that the trial converts to payment. A cost per paying subscriber cannot be directly compared with revenue per install.
In the Payback Calculator, set the billing cycle, customer price, refund assumption, commission assumption, trial behavior, renewal rates, modeled periods and CPA. Confirm the interpretation of each input before comparing scenarios. Rates must be between 0 and 100%; a longer horizon adds more modeled renewals, not more observed evidence.
Separate first renewal from later renewals
The first renewal and subsequent renewals have separate inputs. Treating both as one rate can hide a large initial drop. Future rates are assumptions unless supported by your own cohort data. Keep a record of the time window and population used to estimate them.
Refunds and commission reduce modeled proceeds. Enter assumptions appropriate to your scenario rather than treating an example rate as a current platform policy. The tool does not look up your contract, taxes, settlement terms or bank processing times.
Illustrative example: when a model crosses its CPA
Take a deliberately simple scenario: one acquired paying subscriber, $10 charged per period, no trial, no refunds, a constant assumed 15% commission, and 100% renewal across three periods. Each charge contributes $8.50 in modeled net revenue. Cumulative revenue is $8.50, $17.00 and $25.50 after the three charges.
At a $20 CPA, modeled payback occurs at the third charge. This does not say the money is in your bank on that day, nor that the scenario is commercially realistic. Reducing renewal rates lowers later expected revenue; adding a trial changes when the first charge happens and, depending on conversion, the revenue per acquired user.
Reverse-solve a ceiling
A target ROI of 1.0 means modeled net revenue equals acquisition cost over the selected horizon. A higher target requires a lower CPA ceiling for the same revenue model. You can also ask what CPA fits a target payback day. The ceiling is conditional on the stated assumptions, not a bidding instruction.
Compare A and B fairly
Use the same measurement horizon and acquisition denominator for both plans. Compare the timing of modeled receipts as well as the total. A yearly plan and a monthly plan can produce very different curves even when their final modeled totals look similar. If a scenario does not cross CPA inside the chosen window, report that fact instead of implying eventual payback is guaranteed.
Keep the two LTV models distinct
Retention & LTV projects a retention curve under an ARPDAU assumption. Subscription payback models billing and renewal behavior. Moving between these tools means building another model; it does not make their LTV values interchangeable.
Common questions
Does payback mean profit?
Not necessarily. Operating costs, taxes and other costs outside the model can change the business outcome. Model ROI alone is not evidence that you should scale spend.
Can I share a scenario?
You can export a report or share the supported model-parameter link. A model link exposes the assumptions it carries to its recipient; it is not an uploaded account report.