Customer Acquisition Cost (CAC) for Mobile Apps: Calculate & Benchmark

Customer acquisition cost (CAC) is the single number that decides whether paid growth makes you money or quietly drains it. For mobile subscription apps it’s also one of the most misunderstood, confused with CPI, measured blended when it should be paid, and compared to LTV that was never net of fees and refunds.

This is how I calculate and benchmark CAC for the apps I scale, and the levers that actually move it.

What CAC is, and what it isn’t

CAC is the fully-loaded cost to acquire one paying customer. Not an install, not a trial start, a paying user. That distinction is everything for subscription apps, where the gap between an install and a paid subscriber can be 50× in cost.

• CPI (cost per install), what you pay for a download. A traffic metric, not a business metric.
• CPA (cost per action), cost for a defined event: trial, registration, first open.
• CAC, cost for an actual paying customer, including media, fees and the creative/agency cost to get them.

How to calculate CAC

The basic formula is total acquisition spend divided by new paying customers in the same window:

Two refinements separate a real number from a vanity one. First, use paid CAC (spend ÷ customers from paid) for channel decisions, and blended CAC (all spend ÷ all customers, including organic) for board-level economics. Second, match the time windows, spend in March against customers acquired from that spend, not whoever happened to subscribe in March.

The ratios that matter: LTV:CAC and payback

CAC means nothing alone. It only makes sense against the value a customer returns.

• LTV:CAC, a healthy subscription app targets 3:1 or better on a net LTV (after store fees, refunds and churn).
• CAC payback, how many months of subscription revenue it takes to recover CAC. Under 12 months is the usual bar; the best apps are under 6.
• Contribution margin, what’s left after CAC and variable costs. This is what actually funds the next cohort.

Realistic benchmarks

Benchmarks vary wildly by vertical, geo and price point, so treat these as ranges, not targets. Health & Fitness and AI subscription apps in tier-1 geos often see paid CAC from the low tens to over a hundred dollars per paying user; payback windows that clear inside 6–9 months are strong. The mistake is importing someone else’s benchmark instead of modeling your own economics.

How to actually lower CAC

CAC comes down in a predictable order of impact:

• Creative. The biggest lever by far, a structured testing cadence that keeps fresh winners in market.
• Funnel & paywall. Price testing, onboarding and Web2App flows that lift conversion and LTV, giving you room to bid higher.
• Channel mix. Apple Search Ads for intent, UAC and Meta for scale, TikTok for discovery, weighted by where your paybacks clear.
• Measurement. Fix attribution so you stop scaling channels that only look good in last-click.

Do these in order. Teams that chase a cheaper CPM before fixing creative and measurement just buy more of the wrong users, faster.