Mobile app ROAS & CAC calculator
Turn ad spend and funnel conversion rates into CPI, cost per trial, CAC, LTV, ROAS and payback. Nothing leaves your browser.
Getting downloads without paid customers? Start with the Apple Ads installs-to-subscriptions checklist before changing your campaign assumptions.
CPI
$2
Cost per trial
$17
CAC (per paying user)
$48
LTV per subscriber
$52
Projected revenue
$1,092
ROAS
109%
Payback
7.3 months
Break-even CPI
$2.18
Marginal: you recover spend, but with little room for store fees, churn or slower conversion.
Projection, not measurement. Enter your own conversion rates; blended averages hide which campaigns lose money.
How the numbers connect
- Trials = installs × install→trial rate.
- Paying users = trials × trial→paid rate.
- CAC = spend ÷ paying users.
- LTV = revenue per paid month × expected paid months.
- ROAS = paying users × LTV ÷ spend. Payback = CAC ÷ monthly revenue.
The weak link is almost always the middle of the funnel. Two campaigns with the same CPI can differ 3× in CAC because one brings users who abandon onboarding. See the conversion tracking guide and mobile ad attribution.
To collect campaign data, follow the Google Play Install Referrer guide for Android or the Apple Ads attribution guide for iOS. Check the conversion rates between milestones with the onboarding funnel calculator.
FAQ
- What is a good ROAS for a subscription app?
- Break-even is 100% over the subscriber lifetime. Most teams want 150%+ so store fees, churn and slow payback do not erase the margin. Judge it per campaign, because a blended number hides losers.
- How is CAC different from CPI?
- CPI divides spend by installs. CAC divides spend by paying subscribers. With a 12% trial rate and 35% trial-to-paid, a $2 CPI becomes roughly a $48 CAC, which is the number that has to be beaten by LTV.
- Which LTV should I use?
- Revenue per paid month after store fees, times the average number of months a subscriber keeps paying. Use observed retention from RevenueCat or your billing data rather than a guess.
- Why does the calculator project revenue instead of measuring it?
- Inputs are assumptions. To measure real ROAS per campaign you need spend, onboarding funnel and revenue joined together, which is what OnRamp does.
Want real ROAS per campaign instead of a projection?
OnRamp joins Apple Search Ads, Google, Meta and TikTok spend with your onboarding funnel and RevenueCat revenue.
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