If you have a mobile app and want to earn money from it, you have probably heard about Google AdMob.

But what exactly is AdMob? How does it work? How much can an app earn from ads? What are banner ads, rewarded ads, interstitial ads, and native ads? And what do terms such as eCPM, mediation, app-ads.txt, AdMob Console, and ad units actually mean?

This guide explains Google AdMob from the basics to more advanced concepts in simple language.

What Is Google AdMob?

Google AdMob is Google’s mobile advertising platform that allows app developers to earn money by displaying advertisements inside their mobile apps.

Instead of charging every user to download or use an app, developers can offer the app for free and generate revenue through advertising.

Google explains that AdMob allows developers to create advertising space in their apps, match that space with advertisements, and receive payment for ads displayed to users. AdMob can also work with its own advertising network and third-party ad networks. 

For example, imagine that you create a free Android game.

A player downloads your game and plays several levels. You could show:

• A small banner ad at the bottom of the screen
• A full-screen ad between levels
• A rewarded ad that gives the player extra coins

When eligible ads are shown or interacted with, your app can generate advertising revenue.

Google AdMob vs Google AdSense: What Is the Difference?

Feature	Google AdSense	Google AdMob
Main purpose	Monetizes websites and online content with advertisements	Monetizes mobile applications with in-app advertisements
Designed for	Website owners, bloggers, publishers, and online content creators	Mobile app developers and app publishers
Where ads appear	Websites, blogs, forums, and eligible online content	Android and iOS apps, mobile games, and other supported apps
How you earn	By displaying ads on your website and earning from eligible clicks or impressions	By displaying ads inside your app and earning from eligible ad interactions and impressions
Common example	A technology blog displays ads between its articles	A mobile game displays banner or rewarded ads

How Does Google AdMob Work?

The AdMob process is easier to understand if we break it into a few steps.

Step 1: Create Your Mobile App

First, you need a mobile application.

It could be:

• An Android app
• An iOS app
• A mobile game
• A Unity game
• An app developed using another supported framework

Your app should provide genuine value to users. Advertising is the monetization layer, not the app itself.

Step 2: Create an AdMob Account

You need an AdMob account before you can start setting up advertising.

The account gives you access to the AdMob interface, where you can manage your apps, ad units, reports, mediation settings, and payments.

You can access AdMob through the official Google AdMob website.

Step 3: Add Your App to AdMob

After creating your account, you add your application to AdMob. You can then configure the app and create advertising placements called ad units. An ad unit is essentially a place in your application where an advertisement can be displayed.

For example:

Home screen → Banner ad unit

Between game levels → Interstitial ad unit

Extra coins → Rewarded ad unit

Google describes ad units as containers placed in an app that request and display ads. 

What Is an Ad Unit?

An ad unit is one of the most important AdMob concepts for beginners. Think of an ad unit as a dedicated advertising space inside your application.

For example, suppose you have a news application. You could create:

• Home Banner
• Article Banner
• Article Interstitial
• Rewarded Ad

Each ad unit can have its own unique ID. Your application uses these IDs to request the appropriate advertisement from AdMob.

What Are AdMob Ad Types and Formats?

AdMob supports several advertising formats.

The most important ones for beginners are:

1. Banner ads
2. Interstitial ads
3. Rewarded ads
4. Native ads
5. App open ads

Google’s documentation distinguishes between ad formats and ad types. Ad formats describe how and where ads appear, while ad types describe the kinds of advertising content an ad unit can receive. 

Let’s understand each one.

1. AdMob Banner Ads

A banner ad is a rectangular advertisement displayed within your application’s interface.

For example:

——————————

       Your App Content

       News / Game / Tool

——————————

       Advertisement

——————————

Banner ads are commonly positioned at the top or bottom of an application.

Google currently recommends adaptive banner approaches for many Android implementations because the banner can adjust to the available screen width. 

AdMob Banner Ad Size

Traditional fixed banner sizes include:

Banner Size	Common Use
320 × 50	Mobile banner
320 × 100	Large banner
300 × 250	Medium rectangle
468 × 60	Full banner/tablet
728 × 90	Leaderboard/tablet

These sizes are specified in density-independent pixels for Android.

However, developers should not automatically assume that a fixed-size banner is always the best option. Adaptive banners can adjust based on the available width and device.

2. AdMob Interstitial Ads

An interstitial ad is a full-screen advertisement.

For example:

[ Game Level 1 ] → [ Level Complete ] → [ Full-Screen Advertisement ] → [ Game Level 2 ] 

Interstitial ads can be useful when there is a natural transition in the user experience.

For example:

• Between game levels
• After completing an activity
• Between sections of an app

The important thing is not to interrupt users at inappropriate moments.

3. AdMob Rewarded Ads

Rewarded ads allow users to voluntarily interact with an advertisement in exchange for an in-app reward.

This is particularly popular in mobile games.

For example:

Watch a video to receive 50 coins.

The user chooses whether to watch the advertisement.

Possible rewards include:

• Coins
• Extra lives
• Game energy
• Bonus points
• Unlocking a feature
• Additional game time

Google describes rewarded ads as ads that allow users to receive in-app items for interacting with video ads, playable ads, or surveys.  This is why searches such as “rewarded ads AdMob” is common among game developers.

4. Native Ads

Native ads are designed to fit the visual style and layout of your application. Instead of looking like a separate advertisement, a native ad can be integrated into the application’s content layout while still being identified as advertising.

For example, a news app might display:

• Advertisement
• News Article

The exact design is controlled by the developer within Google’s native advertising requirements. Native ads can be useful when you want advertising to fit naturally into an app’s content experience.

5. App Open Ads

An app open ad is designed to appear when users open or return to an application.

Google describes app open as an ad format that can appear when users open or switch back to an app, overlaying the loading screen.  These ads can be useful for apps where users naturally experience a loading or transition moment.

How Does AdMob Make Money for Developers?

The basic model is simple. Advertisers want to reach potential customers.

AdMob helps match advertisements with available ad space inside applications.

When your application serves eligible advertisements, you can generate revenue.

Google explains that advertisers pay different prices for different ads and that AdMob handles the behind-the-scenes billing process. However, there is no fixed amount that every app earns. 

How Much Does AdMob Pay?

There is no universal “AdMob pays X dollars per 1,000 views” rate.

Your revenue can depend on many factors, including:

• Country of your users
• Type of app
• Ad format
• User engagement
• Number of impressions
• Advertiser demand
• Seasonality
• Platform
• Mediation setup
• Traffic quality

This is why two applications with the same number of users can generate very different amounts of advertising revenue.

What Is AdMob eCPM?

eCPM: Effective Cost Per Mille (“Mille” means one thousand)

In simple language, eCPM estimates how much revenue you receive for every 1,000 ad impressions.

eCPM = (Total Earnings ÷ Impressions) × 1,000 

Example

Suppose your app generates:

• 10,000 impressions
• $20 in estimated earnings

Your eCPM would be:

$20 ÷ 10,000 × 1,000 = $2 eCPM

This does not mean every 1,000 impressions will always produce exactly $2.

eCPM can change over time.

What Factors Affect AdMob eCPM?

Your eCPM can fluctuate because advertising demand changes.

Some important factors include:

1. User Location: Advertiser demand differs between countries and markets.

2. Ad Format: A rewarded ad, banner ad, interstitial ad, and native ad may have different revenue characteristics.

3. User Engagement: How users interact with your application can affect monetization opportunities.

4. Seasonality: Advertising demand can change during different periods of the year.

5. App Category: Different audiences attract different types of advertisers.

6. Mediation: Using multiple eligible ad sources can change competition for available ad requests.

What Is AdMob Mediation?

AdMob mediation allows developers to manage multiple ad sources from one place.

Example: If that network cannot provide an ad, your advertising opportunity may go unfilled.

With mediation, multiple ad sources can compete to serve an advertisement. Google explains that AdMob mediation can use both bidding and waterfall approaches.

What Is AdMob Bidding?

With bidding, participating ad sources compete in a real-time auction to fill an ad request.

For example:

Ad Request

     ↓

Ad Network A ─ $2.10

Ad Network B ─ $2.50

Ad Network C ─ $1.90

     ↓

Eligible winning bid

     ↓

Advertisement

The actual process is more complex than this simplified example, but this helps explain the basic concept.

What Is Waterfall Mediation?

Waterfall mediation uses a sequence of ad sources.

An ad request can move through configured sources according to the mediation setup.

For example:

[Ad Request ] → [Network A]→ [ Network B ]→ [ Network C ]→ [ Advertisement]

Google explains that waterfall mediation calls ad sources one by one based on the configured average eCPM, while bidding allows ad sources to compete in a real-time auction. 

AdMob can also use a hybrid setup containing both bidding and waterfall sources.

What Is the AdMob Console?

The AdMob Console is the management interface where developers manage their app monetization.

Depending on your account and setup, you can use it to work with:

• Apps
• Ad units
• Reports
• Mediation
• Privacy settings
• Account settings
• Payments
• App-ads.txt
• Monetization information

Think of it as your central control panel for AdMob.

What Is AdMob for Android?

If you have an Android application, you can integrate the Google Mobile Ads SDK into your app.

The SDK allows your application to communicate with AdMob and request advertisements.

The general process looks like:

[Android App ] → [Google Mobile Ads SDK] →[AdMob] →[Ad Request] →[ Advertisement] →[User] 

Google provides Android-specific documentation and examples for integrating different ad formats. 

What Is AdMob Unity?

If you develop mobile games using Unity, you can integrate Google Mobile Ads into your Unity project.

Unity is particularly important for mobile game developers because games frequently use:

• Banner ads
• Interstitial ads
• Rewarded ads
• App open ads

Google lists Unity as one of the platforms supported by its AdMob developer resources. 

For a free-to-play game, rewarded advertising can be particularly useful because players can voluntarily watch advertisements in exchange for virtual rewards.

What Are AdMob Test Ads?

This is extremely important for developers.

Never use live advertisements while testing your application.

Google provides dedicated test ad units for development.

For example, Google’s current Android documentation provides a demo ID for an anchored adaptive banner:

ca-app-pub-3940256099942544/9214589741

It also provides a test rewarded ad ID:

ca-app-pub-3940256099942544/5224354917

Google warns developers to use test ads during development because using live ads while testing can result in account problems, including suspension. 

Before publishing your app, replace the test IDs with your actual ad unit IDs.

AdMob Test Banner

If you are developing an Android application and want to test a banner advertisement, Google’s documentation provides a dedicated test banner ad unit.

The current Android test ID for an anchored adaptive banner is:

ca-app-pub-3940256099942544/9214589741 

This is useful when testing whether your implementation works correctly without generating real advertising activity.

What Is app-ads.txt in AdMob?

If you are new to app monetization, app-ads.txt may look confusing.

The simple explanation is:

app-ads.txt helps identify which advertising sellers are authorized to sell your app’s advertising inventory.

Google recommends setting up app-ads.txt for supported apps.

The basic process involves:

1. Have a developer website.
2. Link that website in your app store listing.
3. Create an app-ads.txt file.
4. Add the required authorized seller information.
5. Upload the file to the root of your developer website.
6. Allow AdMob to crawl and verify it.

Google’s current documentation says your app must be registered with Google Play or the Apple App Store and the store listing needs to include a developer website for this verification process.

Where Should app-ads.txt Be Uploaded?

Suppose your developer website is:

example.com

Your app-ads.txt file should generally be accessible at:

example.com/app-ads.txt

Google’s crawler checks the developer website associated with the app’s store listing and looks for the file at the appropriate root-domain location. 

Why Is app-ads.txt Important?

app-ads.txt helps advertisers and advertising platforms identify authorized sellers.

Google’s current AdMob getting-started documentation also notes that apps created after January 2025 that are not verified can face limited ad serving, which can negatively affect revenue. 

Therefore, app-ads.txt should not be treated as an optional technical detail that developers can simply ignore.

How to Start With Google AdMob

If you are a complete beginner, follow this simplified roadmap.

Step 1: Build Your App

Create a useful app or game.

It can be developed using Android, Unity, Flutter, iOS, or another supported technology.

Step 2: Publish or Prepare Your App

Make sure your app follows the relevant app-store and advertising policies.

Step 3: Create an AdMob Account

Sign in to AdMob and create your account.

Step 4: Add Your App

Add or link your application within AdMob.

Step 5: Create Ad Units

Choose the formats you want to use.

For example:

• Banner
• Interstitial
• Rewarded
• Native
• App Open

Step 6: Integrate the Google Mobile Ads SDK

Add the appropriate SDK to your project.

Follow Google’s official documentation for your development platform.

Step 7: Use Test Ads

During development, use Google’s test ad IDs.

Do not test your application using your live production advertisements. 

Step 8: Configure app-ads.txt

Set up your developer website and app-ads.txt correctly.

Step 9: Monitor Your Reports

Once your application is running, monitor:

• Impressions
• Estimated earnings
• eCPM
• Ad requests
• Match rate/fill-related metrics
• Performance by ad format
• Performance by country

How to Increase AdMob Revenue

Increasing AdMob revenue is not about showing more ads. The goal is to balance user experience and earnings.

1. Choose the Right Ad Format

Use ad formats that suit your app. For example, games may use rewarded ads, interstitials, and banners, while content or productivity apps may benefit from native and banner ads.

2. Use Rewarded Ads

Rewarded ads let users choose to watch an ad in exchange for a benefit, such as extra lives, coins, or features. This can provide a better user experience.

3. Avoid Too Many Ads

Showing excessive ads can frustrate users and increase uninstall rates. Focus on strategic ad placements rather than maximum ad frequency.

4. Test Ad Placements

Try different locations, such as between game levels, after completing an action, or at the bottom of the screen, and monitor performance.

5. Track eCPM and Revenue

Don’t focus only on eCPM. Compare eCPM, impressions, and total earnings to understand which setup generates better overall revenue.

Common AdMob Mistakes Beginners Should Avoid

• Clicking Your Own Ads
• Using Live Ads During Development, Always use test advertisements while testing.
• Showing Too Many Ads: Aggressive advertising can damage user experience.
• Ignoring app-ads.txt: Make sure your app-ads.txt file is correctly configured and accessible.
• Looking Only at Downloads: Downloads are not the same as monetization.
• Expecting Guaranteed Income: AdMob revenue isn’t guaranteed.

AdMob for Beginners: Important Terms to Know

Term	Simple Meaning
AdMob	Google’s mobile app monetization platform
Ad unit	A specific advertising space in your app
Ad format	How an advertisement appears
Banner	Small rectangular advertisement
Interstitial	Full-screen advertisement
Rewarded	Advertisement that gives users an in-app reward
Native	Advertisement designed to fit within app content
App Open	Advertisement shown around app opening/resuming
eCPM	Estimated revenue per 1,000 impressions
Mediation	Managing multiple ad sources
Bidding	Ad sources compete in an auction
Waterfall	Ad sources are called in sequence
app-ads.txt	File identifying authorized advertising sellers
AdMob Console	Interface for managing AdMob
Ad unit ID	Identifier used by the app to request an ad
SDK	Software development kit used to integrate advertising

Final Thoughts

Google AdMob provides a way for mobile app developers to turn application usage into advertising revenue.

The basic idea is simple:

Build an app → Get users → Create ad space → Show relevant ads → Measure performance → Optimize monetization

But successful app monetization involves more than simply adding advertisements.

Start with one application, one or two suitable ad formats, proper test ads, and Google’s official implementation guidance. Once your app has real users and enough data, you can use AdMob reports to understand what’s working and gradually improve your monetization strategy.

FAQs