· 14 min read · Samet Durgun · Platform facts checked

How do I calculate a CPA ceiling before I scale an app? It comes from proceeds, not from a benchmark.

I am Samet Durgun, a fractional Head of UA. I run paid UA for subscription apps and mobile games and write up what I find in the accounts I manage. This piece sits under paid UA for subscription apps; more about me.

Take a subscription app with an illustrative $59.99 annual plan. It can afford a $26.87 payer or a $53.81 payer, on the same prices, the same store fees and the same refund rate. The only input that changes is how long it can wait for its money. The most a paying user may cost you is the CPA ceiling, and I set it before I raise spend on any account.

It comes from three numbers you already have. What a payer pays. What reaches you after the store, tax and refunds. How long you can wait for it. A platform target, a benchmark and a 3:1 ratio are none of those things. You set the ceiling first, then the platform target under it, and the gap between the two depends on how old your cohorts are. Every number in the examples is arithmetic on a labeled assumption, not an account.

What is a CPA ceiling, and what is it not?

A CPA ceiling is a cost per paying user, not a cost per install or per trial. Installs and trials are proxies, and I only translate the ceiling into them at the end, through conversion rates measured on cohorts old enough to have converted.

Three things get mistaken for it:

  • A platform target. Google says plainly that with target CPA some conversions cost more than the target and some less. The target is an input to bidding. It has no idea what a payer is worth to you.
  • A benchmark. A median CPI or cost per trial describes other apps, with other prices and other fee tiers. The Tier 2 markets piece shows how a $2 CPI with 3% of installs paying beats a $15 CPI with 4%. That is $67 against $375 per payer. Same benchmark, opposite verdicts.
  • A ratio. I have called 3:1 LTV to CAC a rough guide before, and I will keep calling it that. A ratio hides whether the revenue is proceeds or gross, and when it arrives, which are the two things a ceiling is for.

How do I calculate proceeds per paying user?

Every input in the ceiling is a deduction from the price, and the deductions are bigger and more varied than most models assume.

Store commission. It is not one number. It changes by program, by how long the subscriber has paid, and by region.

Store Rate When it applies
Apple 30% Standard rate, and the first year of any subscription
Apple 15% Small Business Program, for developers with up to $1M in proceeds the year before
Apple 15% Subscriptions after one year of paid service, when your share rises to 85%. Free trial days do not count
Apple, EU 26% Inside the App Store since 1 October 2026, 15% for Small Business and for subscriptions after year one. A 5% Core Technology Commission applies only outside the App Store
Google Play 15% Subscriptions from the first payment in most markets
Google Play, EEA, UK and US 10% + 5% billing fee Subscriptions and the first $1M a year, since 30 June 2026. Australia and Japan since 30 September

A flat 30% in the model is wrong for most apps most of the time, and wrong in the direction that makes you bid too low.

Tax. Where the price includes VAT, the store calculates the commission after the tax comes off, so a €59.99 plan in Germany and a $59.99 plan in Texas do not produce the same proceeds.

Refunds. A refund takes back what reached you. On Google Play, Google returns its service fee on a refunded order. In Apple’s sales reports a refund books negative units at your proceeds rate, so what you lose is your share, not the price the customer paid. RevenueCat’s 2026 report has most categories between 3% and 4%, outliers at 9% to 18%, and higher prices refunding more.

Variable costs. Whatever scales with a paying user: inference for an AI app, content licensing, support. Fixed costs stay out. The ceiling is the break even line per payer, and whatever you bid below it is what pays the rent.

The number left after those four is proceeds per payer. RevenueCat separates the layers the same way, revenue net of refunds, then proceeds after estimated tax and commission, and I build the ceiling on the last one. The money then takes its time. Apple pays within 45 days of the end of the fiscal month in which the sale happened, so a sale can reach you weeks later, and Google Play pays around the 15th of the following month.

How long can you wait for the money?

No benchmark can answer this for you. It is where I spend the most time with a new account.

My rule depends on the plan. A yearly plan pays back on the first payment or it does not pay back at all, so the window is immediate. Weekly and monthly plans put a big share of their value in the first payment and the rest arrives over renewals, so I read them on weekly cohorts and never trust a single week. My rule of thumb, from the Andromeda playbook, is that the average weekly or monthly subscriber returns roughly the yearly price over time. Apps that sell extras on top of the subscription recoup faster, because the second purchase arrives before the renewal would.

Then it depends on the company. For a beginner, recoup everything in the same month. You do not know your renewal curve yet, and the store will not pay you for weeks, so a ceiling that leans on year two is a loan you took from yourself. An established app can stretch toward two years. Established means two things at once. You have at least a year of renewal data, so the curve is known and not guessed, and you have the cash or funding to wait for it. One without the other is not enough.

Counting two years of proceeds is not waiting two years to judge. The target still sits at D30 or D60, as in that playbook, and the measured curve from there to the renewal carries the rest. The window is what the ceiling counts. The day is when you judge.

Measure the renewal curve, because the usual shortcut of revenue per month divided by churn assumes churn stays flat, and in subscription cohorts it does not. Fader and Hardie showed that retention rates rise over time because the people most likely to leave go first. The medians are low too. RevenueCat’s 2026 report has the median first annual renewal between 23% and 40% across the top categories. If your ceiling assumes more than that, I want to see the cohort.

What does the ceiling look like for a $59.99 subscription app?

Every input below is illustrative unless the last column names a source. Replace the rest with your own price list, your own fee tier and your own matured rates.

Input Value Basis
Annual price, US $59.99 Assumption
Monthly price, US $9.99 Assumption
Payer mix 60% annual, 40% monthly Assumption, blended by your actual mix
Store commission 30% in year one, 15% after a year of paid service Apple standard terms
Refunds 4% on first payments, 2% on renewals Assumption, near RevenueCat’s 2026 category medians
Trial to paid 37.4% RevenueCat State of Subscription Apps 2026, median for 5 to 9 day trials
Install to trial 8% Assumption
First annual renewal 35% Assumption, inside RevenueCat’s 2026 range of 23% to 40%
Monthly payments over two years 7 per subscriber Assumption. 7 × $9.99 is $69.93, near the yearly price, which is my rule of thumb
Step Calculation Result
Annual first payment, proceeds $59.99 × 0.70 × 0.96 $40.31
Monthly first payment, proceeds $9.99 × 0.70 × 0.96 $6.71
First payment, blended 60/40 0.6 × $40.31 + 0.4 × $6.71 $26.87 per payer
Per trial at 37.4% $26.87 × 0.374 $10.05
Per install at 8% $10.05 × 0.08 $0.80
Annual payer over two years $40.31 + 0.35 × $59.99 × 0.85 × 0.98 $57.80
Monthly payer, seven payments $6.71 + 6 × $9.99 × 0.70 × 0.98 $47.83
Two years, blended 60/40 0.6 × $57.80 + 0.4 × $47.83 $53.81 per payer
Per trial, two years $53.81 × 0.374 $20.13

The first block is the beginner’s ceiling, same month payback. The second is the established app’s, and it is only available to an app that has watched a cohort for a year and can wait for the second. I kept the 30% commission on all seven monthly payments because monthly plans rarely reach the 15% tier.

What the fee tier does. On the 15% tier, whether through the Small Business Program or as a Google Play subscription, the same first payment is worth $32.63 per payer instead of $26.87. A fifth more headroom from a line in the model that most people leave at 30%.

Illustrative price list from the tables above, Apple standard terms. A full bar is $53.81.

The window doubled the ceiling. The fee tier moved it by a fifth. The trial to paid rate, the input most teams argue about, moved it by nothing, because it only converts the ceiling into a bid. Get the window and the fee right before you touch the funnel rates.

What does the ceiling look like for a mobile game with ad revenue?

Games run on ROAS, and a soft launch has to prove that installs pay back inside the window. So the ceiling is the CPI that still clears the return you need by the day you need it, with purchases and ad revenue both counted. Ad revenue carries no store commission, which is one reason hybrid games can pay more per install than their payer rate suggests.

Illustrative inputs: 3% of installs pay by day 30, a payer spends $35 gross by then, so $24.50 after a 30% commission, and the average install earns $0.40 of ad revenue by day 30. Purchases give 3% × $24.50 = $0.74 per install, ads add $0.40, so an install is worth about $1.14 by day 30.

If day 30 payback is the rule, the CPI ceiling is about $1.14. If you need 130% by day 30 to fund the next cohort, it is about $0.87. Per payer, divide the install value by the 3% who pay, which gives about $38 with ad revenue counted against $24.50 on purchases alone. A model that counts only in app purchases undervalues this game by a third.

In one of my game accounts the CPI stayed flat while D0 ROAS halved, because the order value fell. That is the case for building the ceiling on value per install and not on CPI.

Should the CPA ceiling be the same in every country?

One per country, wherever there is enough volume to read it. Prices differ, tax treatment differs, the store fee can differ, and the plan mix differs, since RevenueCat’s 2026 report has yearly plans at 40% of subscriptions sold in North America and 19% in the Middle East and Africa. Each of those changes proceeds per payer, and a blended ceiling hides the spread. In my country audit one country had run at 28% ROAS for three months inside a campaign that printed 70% blended. On the Videa account I set the ROAS targets by country and let budget follow payback by market.

Where a country is too small to read, blend it with its neighbors and read the group. A country with $80 of spend behind it has a noisy ROAS, not a verdict.

How do I turn a CPA ceiling into a Meta or Google target?

The ceiling is per payer and the platform wants a target per event, so convert first. On trial optimization, cost per trial target = ceiling × matured trial to paid. On purchase optimization, check what the event counts. RevenueCat’s Meta integration sends trial conversions, first purchases and renewals all as Subscribe by default, so a cost per Subscribe can sit below what a new payer really cost, as the optimization event article explains.

Then set the target under the ceiling. How far under depends on cohort age. While cohorts are young, three things are still unknown. The trial to paid rate you multiplied by is a benchmark or a guess, the attribution gap is unmeasured, and refunds have not landed. At that stage the gap under the ceiling does two jobs at once. It absorbs those unknowns, and it is the only money left for fixed costs. So I leave it wide, and I narrow it once a few weeks of matched cohorts have confirmed the rates. In the example, a quarter under the first payment ceiling is about $20 per payer and $7.50 per trial for a young account, and a tenth under is about $24 and $9 once the rates are known. Those margins are illustrative. The direction is not.

In the fitness app I wrote about the target was $15 per trial and I could not get the account below $30. Whether $30 was a failure or fine depended on what a trial was worth to that app. That is the number a ceiling gives you before you spend, not after day 25.

The platforms describe their targets the same way, if you read the footnotes. Meta’s help page calls the cost per result goal and the ROAS goal inputs in the ad auction, with no guarantee the account lands on them. Google’s setup guide tells you to set your tCPA 20% higher than the CPA you observed once data comes in. That is advice on how to win volume. Only the ceiling tells you whether you can afford to.

On Google I start without a target. In my $100K test Max Conversion Value beat tROAS on both platforms and in every market, because tROAS restricts volume before Google has learned anything. The ceiling was the line I judged results against, not a bid input, and I added a target only once there was a return to hold. Google’s own rules point the same way. tROAS on App campaigns needs the Firebase SDK and at least 10 conversions a day or 300 in 30 days.

When is a cohort old enough to judge against the ceiling?

A ceiling built on a 37.4% trial to paid rate is a ceiling for cohorts whose trials have had time to convert. Hold a cohort three days old against it and it will fail every time, and you will cut a campaign that was fine. I compare cost per payer at matched cohort age, the way the D0 against D28 study compares campaigns, and I only let the early number stand in for the late one once the account’s own curve from day 0 to day 28 is known.

The reverse mistake is as common. A cheap cost per trial with a day 0 cancellation rate of 85% is worse than an expensive one at a normal rate, because 55.4% of cancellations in three day trials happen on day 0 and the cheap trial starters are often the ones who cancel. The ceiling is per payer for exactly this reason.

Which numbers do I want before an account scales?

  1. Proceeds per payer. Price by plan and country, your store tier, tax and refunds, blended by your real plan mix. A flat 30% and gross revenue both put the ceiling in the wrong place.
  2. The window. How long you can wait, and whether you have a year of your own renewal data to justify counting more than the first payment.
  3. Matured rates. Trial to paid and install to payer, from cohorts old enough to have converted, per country where the volume allows.
  4. The three ceilings. Per payer, per trial and per install, and how far each moves if the fee tier or the window changes.
  5. The gap to the target. How far under the ceiling the platform target sits, and the cohort age at which you narrow it.
  6. The age you judge at. Cost per payer at matched cohort age, never on the platform’s event alone.

If you can fill in those six lines, you can scale. If you cannot, the growth audit is where I fill them in for an account, and you can book it on its own at any spend level.

Sources and scope

I had each page checked on 4 and 5 October 2026. Store terms change often, so check the date before you quote a rate. The worked examples are arithmetic on labeled assumptions, not an account. The account figures I link to are one account each, not controlled experiments.

Questions people ask

How do I set a CPA ceiling from unit economics before scaling app ad spend?

Start from what one paying user pays, take off the store commission, tax where the price includes it and refunds, and you have proceeds per payer. Decide how much of that you need back and by when, and that is the most a payer may cost. Multiply it by your matured trial to paid rate for a cost per trial, and by your install to payer rate for a CPI.

What is a reasonable CPA ceiling before I increase my ad budget on a subscription app?

There is no reasonable number without your price list. For an illustrative app with a $59.99 annual plan and a $9.99 monthly plan on Apple's standard terms, I get $26.87 per payer if the first payment has to cover the spend and $53.81 if two years of renewals count. Which applies depends on your plan mix, your cash and whether you have a year of renewal data.

Is a 3:1 LTV to CAC ratio a good CPA ceiling?

It is a rough guide for whether a business is set up to scale, not a ceiling. It says nothing about when the cash arrives, and most LTV figures behind it are gross revenue, not proceeds. I set the ceiling from proceeds and a payback window first, and I look at the ratio afterwards, if at all.

Should the CPA ceiling be the same in every country?

No, where volume allows a separate one. Prices, tax treatment, store fees, the plan mix and trial to paid rates all differ by country, so the proceeds per payer differ. In my country audit one country ran at 28% ROAS inside a campaign that printed 70%. I set a ceiling per country where there is enough volume to read, and blend the rest.

How do I turn the ceiling into a Meta or Google target?

The ceiling is per payer. The target is per trial, per purchase event or per install, so convert it through the matured conversion rate first. Then set the target below the ceiling, wide while cohorts are young and narrower once matched cohorts have confirmed the rates. On Google I start without a target at all and judge against the ceiling.