DAU/MAU says what fraction of your monthly users show up on an average day — a number that is 0.6 for a messaging app and 0.05 for a tax product, and both can be healthy.
Of everyone who came to the gym this month, how many turn up on a given day? A ratio of 0.6 is a habit; 0.05 might be a tax product and perfectly healthy.
It's the engagement number hardest to inflate with acquisition, and the easiest to misread across product categories.
Daily and monthly active users are the standard engagement pair, and their ratio — stickiness — measures how many days in a month a typical active user appears. The reason it earns attention is that it is hard to fake with acquisition: you can buy MAU, but buying DAU/MAU requires people to come back. The reason it is dangerous is that it is meaningless without a natural usage frequency. A product genuinely used once a month has a low ratio and no problem; comparing it to a chat app is comparing product categories, not performance.
DAU/MAU is the share of monthly actives present on an average day — a rough measure of how many days a month people use the product. It resists acquisition inflation, which is why it's watched, but it's only interpretable against a product's natural frequency. Track it against your own history, segmented, and always beside retention.
When to Use DAU / MAU Ratio vs. Power User Curves | Eric Andrews Clips — Eric Andrews Clips, 3:23