Mobile app KPIs
and how to calculate them.

Installs

How many people opened your app for the first time.

installs = first-open events in the period

Use it when: you need the denominator for every other rate or want to see whether acquisition is growing.

Daily active users (DAU)

How many different people use your app on a given day.

DAU = unique users with at least one session on the day

Use it when: you track how often people return to the app day to day.

Monthly active users (MAU)

How many different people use your app in a month.

MAU = unique users with at least one session in the month

Use it when: you size the active audience, since it smooths out daily swings.

Stickiness (DAU / MAU)

How much of your monthly audience uses the app on a typical day.

stickiness = average DAU in the month / MAU in the month

Use it when: you judge whether people use the app as a habit or only now and then.

Average session length

How long a typical visit to your app lasts.

session length = time between a session's consecutive events, each gap capped at 5 minutes
average session length = total session length / number of sessions

Use it when: you compare versions of a screen or feature.

Cohort retention

How many of the people who installed in a period come back in a later one.

retention = installs with app activity in a later calendar period / installs in the cohort

Use it when: you judge whether an install source or a new release keeps people.

Cohort analysis tool →

Onboarding completion rate

How many new users finish your onboarding flow.

onboarding completion rate = installs that completed onboarding / installs in the period

Use it when: you judge a new onboarding build against the previous one.

Measure onboarding completion rate →

Onboarding step drop-off

Which step of the flow loses the most people.

step conversion = users at this stage / users at the previous stage
users lost = users at the previous stage - users at this stage

Use it when: you look for the one screen worth redesigning.

Funnel calculator →

Paywall conversion

How many people who see the paywall buy.

paywall conversion = installs that purchased / installs that saw the paywall

Use it when: you change the price, copy or layout of the paywall.

Install-to-purchase conversion

How many installs end up as buyers.

install-to-purchase = installs that purchased / installs in the period

Use it when: you want a single headline number for the whole path from install to purchase.

Time to purchase

How long buyers take to pay after installing.

time to purchase = median of (first purchase - first open), across buyers whose install and purchase both fall in the period

Use it when: you decide when to show the paywall and when to send a reminder.

Trial conversion rate

How many finished free trials turn into paying subscribers.

trial conversion rate = converted trials / (converted trials + cancelled or expired trials), for trials started in the period

Use it when: you judge trial length and the reminder before the first charge.

Measure trial conversion rate →

Trial churn

How many of the trials you start end without a payment.

trial churn = (cancelled trials + expired trials) / all trials started in the period

Use it when: you read it next to trial conversion rate to see how many trials end without a payment.

ARPU

How much revenue each install brings in.

ARPU = revenue in the period / installs in the period
gross revenue = what buyers paid
net revenue = gross minus refunds, taxes and store fees

Use it when: you compare periods, apps and countries, since revenue per install differs by country.

ARPU calculator →Country pricing tiers →

Refund rate

How many paid purchases get refunded.

refund rate = refunded paid transactions / paid transactions created in the period

Use it when: you want to catch a pricing, copy or billing problem early.

Subscriber churn rate

How many paying subscribers you lose in a period.

subscriber churn rate = subscribers who cancelled or expired in the period / subscribers at the start of the period

Use it when: you judge how well the app keeps paying subscribers after they convert.

Monthly recurring revenue (MRR)

How much predictable subscription revenue you earn each month.

MRR = sum of the monthly price of every active subscription
monthly price of an annual plan = annual price / 12

Use it when: you track the growth of subscription revenue from one month to the next.

Customer lifetime value (LTV)

How much revenue an average subscriber brings in over their whole time as a customer.

LTV = average monthly revenue per subscriber / monthly subscriber churn rate

Use it when: you decide how much you can afford to spend to acquire a subscriber.