What is CPI? (Cost Per Install Explained)

CPI—Cost Per Install—is the amount you pay to acquire one app install through paid advertising.

It's the most basic unit economics metric in mobile user acquisition. If you spent $1,000 on ads and got 250 installs, your CPI is $4.

The formula is straightforward:

CPI = Total Ad Spend / Number of Installs

But understanding what makes a "good" CPI requires context. A $2 CPI might be excellent for a casual game and catastrophic for a finance app.

Why CPI Matters

CPI is your first signal about acquisition efficiency. It tells you how much it costs to get someone to install your app, which is the starting point for all downstream metrics like retention, conversion, and LTV.

When CPI is too high relative to your LTV, you're burning money. When it's too low, you might be leaving growth on the table by not spending aggressively enough.

The metric itself is simple. The challenge is knowing what your target should be and how to improve it.

How CPI is Calculated

Every ad platform calculates CPI the same way:

CPI = Total Campaign Spend / Total Installs Attributed to That Campaign

If you spent $5,000 on a Meta campaign and got 1,250 installs, your CPI is $4.

Most platforms (Meta, Google, TikTok, Apple Search Ads) show CPI automatically in their dashboards. You don't need to calculate it manually unless you're aggregating across multiple channels.

Attribution Window Considerations

CPI depends on attribution. If you're using a 7-day click attribution window, installs that happen within 7 days of a click count toward CPI. Shorter windows (1-day click) will show higher CPI because fewer installs get attributed.

Make sure you're comparing CPI across campaigns with the same attribution settings. A 1-day CPI and a 7-day CPI aren't the same metric.

2025 CPI Benchmarks by Category

CPI varies significantly by platform, geography, and app category. Here's what the data shows for 2025:

Platform Averages

Platform	Average CPI
iOS	$3.50 - $4.70
Android	$2.70 - $3.40

iOS CPI is approximately 30% higher than Android, primarily because iOS users are concentrated in wealthier markets with higher competition and better monetization potential.

Category Benchmarks

App Category	Average CPI
Finance	$8.70
Gaming (Overall)	$3.90
Entertainment	$1.10
Shopping/eCommerce	$1.30

Gaming CPI by Genre (2025)

Game Type	iOS CPI	Android CPI
Hyper-Casual	$2.50	$1.50
Strategy	$5.50	$4.00
Action	$4.50	$3.00
RPG	$6.00	$4.50
Simulation	$3.75	$2.50
Arcade	$3.00	$2.00

Source: Business of Apps, Mapendo, Sensor Tower (2025 data)

Why CPI Varies by Category

Finance apps have the highest CPI ($8.70) because users are more valuable. The average LTV for a finance app user can be $100-$300+, which justifies higher acquisition costs.

Entertainment and shopping apps have the lowest CPIs ($1.10-$1.30) because they monetize through ads or quick transactions, which means lower LTV and tighter margins on acquisition.

Gaming sits in the middle. Hyper-casual games have low CPI because they monetize through ads at scale. Strategy and RPG games have higher CPI because they rely on in-app purchases from a smaller subset of highly engaged users.

What Drives CPI Up or Down

Several factors affect your CPI:

Competition: More advertisers targeting the same audience = higher CPI.

Creative quality: Strong, scroll-stopping creative lowers CPI by improving click-through rates and conversion rates.

Targeting precision: Broad targeting tends to increase CPI because you're reaching less relevant users. Tight targeting can lower CPI if you're reaching high-intent audiences.

Seasonality: CPI spikes during Q4 (November-December) as advertisers compete for holiday spending. January typically sees lower CPIs.

Geography: Tier 1 markets (US, UK, Canada, Australia) have CPIs 3-5x higher than Tier 2/3 markets (Latin America, Eastern Europe, Southeast Asia).

Platform maturity: Newer ad platforms (like TikTok in 2020) often have lower CPIs early on before they reach market saturation.

CPI vs CPA: What's the Difference?

CPI measures cost per install. CPA (Cost Per Action) measures cost per specific action—like a subscription, purchase, or registration.

CPI is a top-of-funnel metric. It tells you how much it costs to get someone to install.

CPA is a mid-funnel or bottom-funnel metric. It tells you how much it costs to get someone to do something valuable after they install.

For apps that monetize through subscriptions or purchases, CPA is usually more important than CPI. A $10 CPI might seem high, but if your CPA for a paying user is $30 and your average subscription value is $100, the economics work.

For ad-monetized apps, CPI is often the primary metric because every install has immediate value through ad impressions.

When CPI Alone Isn't Enough

CPI is useful for comparing acquisition efficiency across channels, but it doesn't tell you anything about user quality.

A $2 CPI with 10% Day 1 retention is worse than a $4 CPI with 40% Day 1 retention.

This is why most growth teams track CPI alongside:

• Retention rates (Day 1, Day 7, Day 30)
• LTV (Lifetime Value)
• Payback period (Time to recover CPI through user revenue)
• ROAS (Return on Ad Spend)

CPI tells you what you're paying. These other metrics tell you if it's worth it.

How to Lower Your CPI

If your CPI is higher than benchmarks or too high relative to your LTV, here's what typically moves the needle:

1. Improve creative performance

Test new ad formats, hooks, and messaging. Creative is the highest-leverage input for lowering CPI because it directly affects CTR and conversion rate.

2. Refine targeting

Broaden if you're targeting too narrowly (not enough scale). Narrow if you're targeting too broadly (low relevance).

3. Optimize your app store page

A higher install conversion rate means more installs per click, which lowers CPI. Small improvements to screenshots or videos can reduce CPI by 10-20%.

4. Test new channels

If Meta CPI is $6 and Apple Search Ads CPI is $3, shifting budget to ASA lowers blended CPI.

5. Adjust bid strategy

Switching from cost cap to bid cap (or vice versa) can improve CPI depending on your campaign structure and platform algorithm.

Key Benchmarks to Remember

• iOS CPI averages $3.50-$4.70; Android averages $2.70-$3.40
• Finance apps: $8.70 CPI
• Gaming apps: $3.90 average, ranging from $1.50 (hyper-casual Android) to $6.00 (RPG iOS)
• Entertainment and shopping apps: $1.10-$1.30
• Tier 1 markets have CPIs 3-5x higher than Tier 2/3 markets
• Q4 CPIs are typically 20-40% higher than Q1

FAQs

What is CPI in mobile marketing?

CPI (Cost Per Install) is the amount you pay to acquire one app install through paid user acquisition campaigns. It's calculated by dividing total ad spend by the number of installs generated.

What's a good CPI for mobile apps?

Average CPI varies by platform and category. iOS averages $3.50-$4.70, while Android averages $2.70-$3.40. Gaming apps average $3.90, entertainment apps $1.10, and finance apps $8.70. What's "good" depends on your LTV and monetization model.

Why is iOS CPI higher than Android?

iOS CPI is approximately 30% higher than Android, averaging $3.50 vs $2.70, primarily because iOS users are concentrated in wealthier markets (US, UK, Western Europe) with higher competition and better monetization potential.

Should I optimize for CPI or CPA?

If your app monetizes through subscriptions, purchases, or registrations, optimize for CPA. If you monetize through ads, CPI is more relevant. Most apps should track both but prioritize the metric closest to revenue.

How do I calculate CPI?

CPI = Total Ad Spend / Number of Installs. If you spent $1,000 and got 250 installs, your CPI is $4. Most ad platforms calculate this automatically.

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CPI is the foundation of mobile user acquisition economics. It's not the only metric that matters, but it's the starting point for understanding if your acquisition strategy is sustainable.