User acquisition cost for a mobile app is everything you spend on winning new users in a period, divided by the number of new users you won in that period. There is no single "average" worth planning around, because the answer changes with what you count as a user (an install, a trial or a paying customer), your category, your platform and your channel, so the useful work is calculating your own figure and comparing it with what a user earns you.
What is user acquisition cost for a mobile app?
User acquisition cost (UAC) is the average amount you spend to gain one new user. The formula is simple:
User acquisition cost = total acquisition spend in a period ÷ new users acquired in that period
The hard part is not the division. It is agreeing on the two inputs.
Which "user" are you counting?
The same month of spend produces very different numbers depending on where you draw the line:
- Per install. Spend divided by installs. This is cost per install (CPI), and it is the figure most ad platforms report.
- Per trial or sign-up. Spend divided by users who started a trial or created an account.
- Per paying customer. Spend divided by users who actually paid. This is what most people mean by customer acquisition cost (CAC).
For any app that earns money from purchases or subscriptions, cost per paying customer is the number that decides whether a channel is working.
Is user acquisition cost the same as customer acquisition cost?
In mobile, the two terms are often used for the same thing, but they are not always the same number. "User acquisition cost" usually refers to cost per install or per new user. "Customer acquisition cost" usually refers to cost per paying customer. If someone quotes you a figure, ask which event it is counted against before you compare it with your own.
How do you calculate app user acquisition cost?
Work through it in four steps, using one fixed period (a calendar month is easiest).
- Add up everything you spent on acquisition in the period.
- Count the new users gained in the same period, at each stage: installs, trials, paying customers.
- Divide spend by each count to get cost per install, cost per trial and cost per paying customer.
- Repeat per channel, so one expensive channel cannot hide behind a cheap one.
What costs should you include?
A calculation that only counts ad spend makes every channel look better than it is. A fully loaded figure includes:
- Media spend on every ad platform
- Creative production (video editing, design, user-generated content you paid for)
- Agency and freelancer fees
- Salaries, or the share of salaries, of people working on acquisition
- Tools: measurement, analytics, creative testing, link and affiliate tooling
- Creator fees, free product and commissions or referral rewards paid out
Keep two versions of the number. Paid CAC uses only the spend and the users from paid channels, and tells you how efficient your buying is. Blended CAC divides all spend by all new users, including those who arrived organically, and tells you what growth costs the business overall. Blended always looks better, so never use it to judge a single campaign.
A worked example (hypothetical)
The numbers below are invented to show the arithmetic. They are not benchmarks.
Say your subscription app charges $9.99 a month and, in one month, you spend:
| Cost | Amount |
|---|---|
| Ad spend | $7,000 |
| Creative production | $1,500 |
| Freelance media buyer | $1,000 |
| Tools | $500 |
| Total | $10,000 |
Paid campaigns bring 2,500 installs, of which 100 become paying subscribers. A further 1,500 installs arrive organically, and 40 of those subscribe.
| Metric | Calculation | Result |
|---|---|---|
| CPI as the ad platform reports it | $7,000 ÷ 2,500 | $2.80 |
| Fully loaded cost per paid install | $10,000 ÷ 2,500 | $4.00 |
| Paid CAC (per paying subscriber) | $10,000 ÷ 100 | $100.00 |
| Blended CAC | $10,000 ÷ 140 | $71.43 |
The dashboard says $2.80. The business is paying $100 for each customer that paid channels bring in. Both are true, and only the second tells you whether to keep spending.
What is the difference between CPI, CAC and payback period?
These three answer different questions, and each one is incomplete without the others.
| Metric | Formula | What it tells you | What it hides |
|---|---|---|---|
| CPI | Ad spend ÷ installs | How cheaply you can buy downloads | Whether those downloads ever pay |
| CAC | All acquisition spend ÷ new paying customers | What a paying customer really costs | How long it takes to earn the money back |
| Payback period | CAC ÷ monthly net revenue per paying customer | How many months until a customer has repaid their acquisition cost | What happens after payback (retention and total lifetime value) |
How do you work out payback period?
Use net revenue, not the list price. The app stores keep a commission on in-app purchases before you are paid. Apple's App Store Small Business Program sets a reduced commission rate of 15% for developers who earned up to 1 million USD in proceeds in the prior calendar year, and Google Play's service fee is 15% on automatically renewing subscriptions and on the first $1M (USD) a developer earns each year.
Continuing the hypothetical example: $9.99 less a 15% store commission leaves about $8.49 a month. With a paid CAC of $100, payback is $100 ÷ $8.49, or roughly 12 months, and that assumes the subscriber stays for the whole year. If many subscribers cancel in month three, the money is never recovered.
That is why CAC only means something next to customer lifetime value. A high acquisition cost is fine when users stay and pay for a long time. A low one is still a loss if they never pay at all.
How much does mobile user acquisition cost? The benchmarks that can be verified
Most "average CPI by category" tables online repeat figures from other articles without a link to the original data, and they vary with whose campaigns were measured and in which countries. We have left those out. The figures below come from two annual industry reports, each linked, with the year stated. Your own cost per paying customer, measured per channel over a few months, remains a better benchmark than any published average.
How much do apps spend on user acquisition overall?
AppsFlyer's app marketing trends release for 2025, published in December 2025, reports that global user acquisition spend rose 13% to $78 billion. The same release says:
- iOS user acquisition spend grew 35%, while Android remained flat.
- Non-gaming apps increased their spend 18% to $53 billion, while gaming grew 3% to $25 billion.
AppsFlyer states that the analysis is based on 32 billion paid app installs across 45,000 apps.
How many installs turn into paying customers?
This is the figure that converts a cost per install into a cost per customer. RevenueCat's State of Subscription Apps 2026, built on data from over 115,000 apps, reports these medians for download-to-paid conversion by day 35:
| Segment | Median download-to-paid conversion by day 35 |
|---|---|
| Apps with a hard paywall | 10.7% |
| Freemium apps | 2.1% |
| Developers based in North America | 2.6% |
| Developers based in Western Europe | 2.0% |
| Developers based in India and South East Asia | 1.4% |
The arithmetic is unforgiving. If 2 in every 100 installs pay, then your cost per paying customer is about 50 times your cost per install. An app that pays $3 per install and converts at 2% is paying $150 per customer.
How much revenue does an install bring in early on?
The same RevenueCat report gives a median revenue per install of $0.23 at day 14 across all categories, with Health and Fitness at $0.48 and Gaming at $0.08. Set that beside whatever you pay per install and the gap shows how much of the return has to come from later renewals, not from the first fortnight.
How does app user acquisition cost differ by channel?
Channels differ less in price than in when you pay and who carries the risk if users do not convert.
| Channel | What you pay for | When you pay | Who carries the risk of non-paying users |
|---|---|---|---|
| Paid social (Meta, TikTok and similar) | Ad delivery, optimised towards installs or in-app events | As ads run | You |
| App store search ads | Taps on your ad | As taps happen | You |
| Google App campaigns | Bids set around a target cost per install or per in-app action | As ads run | You |
| Flat-fee creator sponsorships | A post or video | Upfront | You |
| Affiliate and creator revenue share | Purchases and subscriptions the partner drives | After the sale | The partner |
| Referral rewards | Successful referrals from existing users | After the referral converts | Shared |
How do the ad platforms charge?
Apple's documentation for its App Store search ads explains that you set a maximum cost-per-tap bid and pay only when someone taps your ad. A tap is not an install, so your real cost per install depends on how many people who tap go on to download.
Google's help pages for App campaigns describe two options: a target cost per install, and a target cost per action for campaigns aimed at a specific in-app event. A target is an average the system steers towards, not a guaranteed price.
In every one of these, you are billed whether or not the user ever buys anything. Optimising towards purchase events improves the odds. It does not move the risk.
Why is affiliate marketing a pay-on-results channel?
With a revenue share arrangement, the cost of acquisition is a percentage of a sale that has already happened. There is no bill for installs that never convert, and the acquisition cost is known in advance as a share of revenue.
Go back to the hypothetical $9.99 subscription. Under a 30% revenue share, the affiliate earns about $3.00 for each month the subscriber pays. After a 15% store commission ($1.50), you keep about $5.49 from the first payment onwards. There is no $100 to earn back, and if the subscriber cancels, the commission stops too.
The trade-offs are real. You need partners whose audience fits your app, volume builds more slowly than a paid campaign you can switch on today, and you give up margin on every sale for as long as the commission runs.
This is the job Insert Affiliate does for mobile apps. It tracks the in-app purchases and subscriptions that each affiliate, creator or referring user drives on iOS and Android, along with Stripe purchases on the web, and calculates their commission. According to the commission documentation, you can set a percentage or a fixed amount per sale, choose per affiliate whether renewals earn commission or only the first purchase, and decide whether commission is calculated before or after store fees. If you want to reward downloads as well, optional install event payments pay a flat fee per install, with a cap you control. Payouts can be made from the dashboard, and automatic payouts are available if you choose to switch them on.
Sean Adkinson, CTO and Co-Founder of Stop Loss Tracker, puts the appeal this way: "Insert Affiliate is solving a real problem by combining affiliate tracking across all my app's revenue sources."
How can you lower your mobile app user acquisition cost?
Lowering the cost per paying customer comes from either paying less per install or converting more of the installs you already buy. The second is usually the bigger lever.
- Measure per channel, per paying customer. A channel with a higher CPI can still be the cheapest source of customers if its users convert better.
- Fix conversion before buying more traffic. Onboarding, paywall placement and trial design change how many installs pay, and every improvement lowers CAC on all channels at once.
- Improve retention. Longer-lived subscribers shorten payback and raise the acquisition cost you can afford.
- Shift some spend to pay-on-results channels. Affiliates, creators on revenue share and referral rewards put a ceiling on what a customer can cost you.
- Invest in organic. App store optimisation and content take time, but each user they bring in pulls your blended cost down.
- Match the channel to the category. In verticals where people follow trusted voices, such as fitness apps, creator partnerships tend to fit naturally.
Frequently asked questions
What is a good user acquisition cost for a mobile app?
A good user acquisition cost is one your app earns back with room to spare, within a period your cash can cover. That depends on your price, your store commission and how long users stay, so there is no universal figure. Work out your net revenue per paying customer and your payback period first, then judge each channel against those.
What is the difference between CPI and CAC?
CPI (cost per install) is ad spend divided by installs. CAC (customer acquisition cost) is all acquisition spend divided by new paying customers. CAC is always higher, often by a wide margin, because only a small share of installs go on to pay.
What is a CAC payback period?
It is the number of months it takes for a customer's net revenue to cover what you spent acquiring them. Divide CAC by monthly net revenue per paying customer, using revenue after app store commission. A shorter payback means you can reinvest sooner and are less exposed to cancellations.
Why is my cost per paying user so much higher than my CPI?
Because most installs never pay. RevenueCat's State of Subscription Apps 2026 puts median download-to-paid conversion by day 35 at 2.1% for freemium apps and 10.7% for apps with a hard paywall. At a 2% conversion rate, cost per paying user is roughly 50 times cost per install.
Is affiliate marketing cheaper than paid ads for app user acquisition?
Not necessarily cheaper per customer, but the cost arrives differently. With paid ads you pay first and find out later whether users convert. With a revenue share affiliate programme you pay a known percentage after a purchase, so the cost of a customer can never exceed the revenue they bring in.
Your next step
Take last month's numbers and calculate three things per channel: cost per install, cost per paying customer, and payback period on net revenue. If one channel's payback is longer than your typical subscriber stays, cut it or fix conversion before spending more. If you would like to test a channel where you pay only on results, Insert Affiliate is free to start.