Monthly Active Users (MAU)
Unique users who engage with your product at least once in a calendar month.
Vanity Risk
MAU is the textbook vanity metric: it grows with any one-time visit and never falls as long as acquisition outruns lapse, so it can rise for months while engaged usage shrinks. Never report MAU without a stickiness or retention companion.
What it measures
The size of your active user base over a month. As with DAU, what counts as "active" is product-specific—a login, a content view, or a core action—and the definition must stay consistent to compare months. MAU is the standard denominator for reach and the base for the DAU/MAU stickiness ratio, but on its own it says nothing about how often or how deeply those users engage.
What to watch
- Rising: Your reach is growing. But MAU counts a user who showed up once the same as a daily power user, so confirm the growth is engaged by checking DAU/MAU stickiness and retention curves alongside it.
- Falling: Either acquisition slowed or existing users are lapsing. Decompose with growth accounting (new vs. resurrected vs. churned) to tell a top-of-funnel problem from a retention problem—the fix is different for each.
When NOT to use
For high-frequency products where daily habit is the goal, DAU is the more honest headline—MAU can look healthy while daily engagement quietly erodes. For deliberately infrequent products (tax software, travel booking), monthly counts swing with seasonality and a rolling-30-day window reads better than a calendar month.
In practice
A B2B tool celebrated MAU climbing past 50,000, but DAU/MAU stickiness was stuck at 8%—most "monthly active" users logged in once and never returned that month. The team reframed their North Star from MAU to weekly active users who completed a core action, which exposed that real engaged usage was a fraction of the headline number and redirected the roadmap toward activation rather than top-of-funnel acquisition.
Illustrative scenario — a representative composite, not a specific company.
Related: DAU — the daily counterpart; MAU is the monthly denominator, DAU the daily numerator.; DAU/MAU Stickiness — MAU is the denominator; the ratio is what turns a raw reach count into a habit signal.; Growth Accounting — decomposes MAU change into new, resurrected, retained, and churned users.