CPI Budget Planner

Budget = installs × CPI looks trivial, but each variable hides structure. CPI varies by channel (Apple Search Ads, Meta, and Google App Campaigns all behave differently), by geography (US iOS commonly $2–5 for broad targeting while many emerging markets sit under $0.50), by platform (iOS typically 1.5–3× Android), and by season (Q4 auction pressure raises CPIs alongside eCPMs). A single blended CPI is fine for a first sizing pass, but a real plan prices each channel-and-geo cell separately and sums them.

Beware the small-test trap: a $500 pilot buys the cheapest available users, so the CPI you measured there understates what the next $50,000 will cost. Marginal CPI rises with scale as targeting exhausts the easy audience — budgeting with a 20–50% CPI escalation buffer for meaningful scale-ups keeps the plan achievable instead of aspirational.

Installs are an intermediate metric — the plan should be sized from the outcome behind them. Working backwards: if you need 500 new subscribers and 4% of installs subscribe, you need 12,500 installs; at a $3 CPI that’s a $37,500 budget. Running the chain in this direction also surfaces the cheapest fix — improving install-to-subscriber conversion from 4% to 5% cuts the required budget by 20% without negotiating a single bid.

Finally, treat paid installs as one input alongside organic, not the whole plan. Paid campaigns typically lift organic downloads too (chart movement, search familiarity), while strong ASO reduces the paid volume needed to hit the same total — so a budget built on paid-only math overspends. The teams with the lowest blended cost per install are almost always the ones whose organic base carries the majority of volume.