whatiscpm.com

Metric wiki

CPM vs CPI

By Oliver Wakefield-Smith · updated July 2026

The short answer

CPI, cost per install, is app marketing's CPA: you pay when the app lands on a device. Underneath, the ad networks are still clearing an impression auction and converting your install bid into an effective CPM. Run the back-calculation yourself: CPI times install rate times 1,000 is the implied CPM you are paying for the inventory.

implied CPM = CPI × installs-per-impression × 1,000

$2 CPI at 0.5% installs-per-impression = $10.00 implied CPM

$2 CPI at 0.1% installs-per-impression = $2.00 implied CPM

CPI and install rates are stated inputs for the mechanism; measure your own funnel in your MMP dashboard before trusting anyone's benchmark table.

Why the back-calculation matters

Glossaries define CPI and stop; the implied CPM is where decisions live. If your CPI campaign implies a $10 CPM on inventory the same network sells outright at $4, you are paying $6 per thousand for the network to carry the conversion risk. Sometimes that insurance is worth it (unproven creative, new geo); sometimes it is a lazy tax. You cannot know until you compute the implied number, which takes your MMP's install rate and thirty seconds in the calculator.

On CPI benchmark tables

Published CPI benchmarks (Business of Apps aggregates the research lane) swing by platform, geography, category and month, and most circulating tables are undated republications of each other. Per this site's standing rule, we print no CPI figure without a dated primary source we would defend, and we found none current enough to stand here today. The mechanism above is stable; the numbers are yours to measure.

When to buy installs on CPM instead

  • Proven funnel: once your store-page conversion and creative CTR are known quantities, CPM buying pockets the risk premium the CPI network was charging.
  • Unproven anything: pay the CPI insurance and let the network eat the variance.
  • Same logic, other letters: this is the CPC risk trade (worked here) and the CPA cascade (worked here) wearing app-store clothes. Mobile-heavy channels to apply it on: TikTok and Facebook.