important metrics for app monetization

Does it seem to you like the number of acronyms populating app development discussions keeps on relentlessly increasing? We at AdtoApp feel your pain.

So, here are the 11 most fundamental formulas and metrics for app monetization, divided into two categories: in*-app monetization metrics, and advertising metrics.

[b]Monetization metrics

  1. LTV, LT, eCPI, K[/b]

LT​ is ‘lifetime,’ or the period of time, normally calculated in months, for how long someone uses your app before they stop using it. The longer someone uses your app, the better your stats will be. You’ll see why LT is important when calculating the next formulas.

eCPI​is the ‘effective cost per install’ or how much it’s costing you to get a new user to use your app. It’s different from C​PI​ (cost per install), because a good app maker does not pay for each and every new user, there is a viral effect of word* of* mouth that helps drive installs too. This is known as the K​factor, ​or the viral coefficient. To figure out your e​CPI, divide your CPI by K.​

LTV​ might be one of the most important indicators, and it stands for ‘lifetime value’ of a user of your app, or how much each user is worth to you over the course of the time that they will use your app. It’s easy to calculate your L​TV: monthly revenue per user * monthly expenses per user, like CPI) x lifetime (in months).


ARPU​is ‘average revenue per user’ and is n​ormally cited in terms of months.​ Therefore, the calculation is m​onthly revenue divided by MAU (monthly active users). ​Many apps that have multiple tiers segment their users between paying and non*-paying users. If this is the case with your app, then you are probably looking at A​RPPU,​ or ‘average revenue per paying user.’ This is dividing the revenue by the number of people who paid something, which will end up making your A​RPPU much larger than your ARPU​ because it’s not diluted by all the free users.

3. FUUU factor

In gaming, the FUUU Factor is an important measurement of how people continue to interact with your game. It’s a general scale of difficulty for different levels, and a g​ood gaming app maker will use this​to their advantage.

4. Churn rate, retention rate, return rate

The r​etention rate​is just like it sounds, it’s the n​umber of people who install your app​ today, use it, and then come back and use it tomorrow. And the day after that, etc. Since it’s a percentage, retention of a cohort (the people who sign up on any given date) will decline over time. This is due to c​hurn,​or when people stop using your app and switch to something else. The formula to calculate c​hurn is 1 minus your retention rate.​

The r​eturn rate ​is a ratio of the n​umber of your users who are active​during a given time period relative to the size of their cohort group. This is particularly useful for optimizing your marketing because you can see which users became more active depending on when and from where they installed.

5. Duration and engagement

Duration ​is similar to LT; it’s the average number of months someone uses your app. The established calculation is 1​ divided by your churn rate. ​E​ngagement ​is probably the most straightforward. It’s usually measured by D​AU​ (daily active users) or M​AU​ (monthly active users); whichever number sounds better is usually the one to go with!

Advertising Metrics
6. eCPM

eCPM is ‘effective cost per mille (thousand)’ which is a variation on the traditional CPM, or how much it costs to reach 1,000 users. When a campaign is expressed in CPM, then the e​CPM is exactly the same.​ When a campaign is CPC (cost per click) there is an effective CPM because even users that don’t click still see an ad.

7. Fill rate

Fill rate is the efficiency of ​delivery of the actual ad ​to the eyes of a user. Fill rate is calculated as the number of ads delivered divided by the number of ads requested.


These are all classic measurements from the online space that apply to mobile apps as well. CTR is ‘click through rate,’ or h​ow many people click a link. ​It’s used to measure the effectiveness of advertising campaigns. CPC is “cost per click” and results on a payment being made from the advertiser to the publisher each time a user clicks through to their content. CPI is “cost per install” and is another way of publishers being paid when one of their users clicks an ad in their app which results in the download and installation of another app.


As we talked about above. D​AU​(daily active users) or M​AU​(monthly active users) are a measurement of engagement. With these numbers, the higher the better.

10. Length of session

While it has much less importance than DAU or LTV, l​ength of session ​will help you segment your users to study how people use your app differently. It’s more helpful for product development than monetization or advertising.

11. Refresh rate

The r​efresh rate ​is h​ow often you deliver a new ad​ to your user. This can range from every 30 seconds to every 180 seconds.

Common sense would say to have ads refresh as much as possible, in order to increase revenue. But this can come at the expense of user experience, and so optimization is important. Advertisers also prefer to not have their impressions cut short and to give the user enough time to engage with the ad.