How is Daily Active Users (DAU) calculated?

In Zitadel, we use a "Sum of DAUs" model. This means we don't just count if a user was active once during the month; we look at how many individual days they were active. This provides a more fair, usage-based pricing for different types of applications.

Understanding how Daily Active Users (DAU) translates to your monthly bill can be confusing, especially since most of the industry uses Monthly Active Users (MAU).

What is a "Daily Active User" (DAU)?

A user is considered "active" on a specific day if they perform an authentication event. Specifically:

Logging in (using a local account or an external provider like Google or Microsoft).
Refreshing a token (when an application keeps a user logged in).
Service User authentication (Machine-to-Machine API access).

Key Rule: Each unique user is only counted once per day, no matter how many times they log in or refresh tokens within that 24-hour period.

How Your Monthly Bill is Calculated

To calculate your monthly total, we sum the DAU count of every single day in that month.

The Formula:

Monthly Billing Total = Day 1 DAUs + Day 2 DAUs + ... + Day 31 DAUs

Example Calculation:

Imagine you have one user, "Alice":

April 1st: Alice logs in 5 times. → 1 DAU
April 2nd: Alice does nothing. → 0 DAU
April 3rd: Alice logs in once. → 1 DAU

Total for these 3 days: 2 DAUs (whereas under an MAU model, this would simply be 1 MAU).

Comparing Industry MAU vs. Zitadel DAU

The main difference is how "return visits" are treated.

Feature	Monthly Active Users (DAU)	Sum of Daily Active Users (DAU)
User logs in 1 day/month	Counts as 1 unit	Counts as 1 unit
User logs in 20 days/month	Counts as 1 unit	Counts as 20 units
Fairness	High-usage apps pay the same as low-usage apps.	You pay based on how often your users actually use the system.

How to Convert MAU to DAU (Estimation)

If you are coming from an MAU-based provider, you can estimate your Zitadel DAU needs using this logic:

Formula:
Total Monthly DAUs = (Your Current MAU) × (Average days a user logs in per month)

Low-Frequency App (e.g., HR Portal): Users log in roughly 2 times a month.
- 1,000 MAUs × 2 days = 2,000 Monthly DAUs
High-Frequency App (e.g., Slack Clone): Users log in every weekday (20 days).
- 1,000 MAUs × 20 days = 20,000 Monthly DAUs

For a more detailed breakdown, see our guide on How to convert Monthly Active Users (MAU) to Daily Active Users (DAU).

Frequently Asked Questions

Do Service Users count? Yes. If a machine-to-machine service authenticates, it is counted as 1 DAU for that day.
What if I use External IdPs (Google, Entra ID)? You are only charged once. If a user logs in via Entra ID, it counts as 1 DAU for the user; we do not charge "extra" for the local representation of that user.
How can I track this? You can view your current DAU and MAU metrics directly in the Analytics section of your Zitadel Management Console to help predict your upcoming bill.