Monthly active users, usually abbreviated to MAU, is the number of distinct people who use a digital product at least once during a month, measured either as a rolling 30-day window or a calendar month. Each person is counted once, however many times they return. The metric exists because raw sign-ups say little about whether anyone still uses a service. MAU is the figure consumer internet companies put in front of investors, advertisers and, since 2023, European regulators to describe how big they really are.

How the count works

Every MAU figure rests on three decisions. The first is the identity being counted: a logged-in account, a device, a browser cookie or an estimate of a real person. The second is the qualifying action: opening an app, loading a page, sending a message or simply being exposed to content. The third is the window and how it is reported, whether as the total at the end of a quarter or an average of monthly totals across it.

A product logs an event each time an identifier performs a qualifying action. At the end of the window, analysts deduplicate the identifiers and count what remains. The hard part is the deduplication. One person using a phone app, a laptop browser and a tablet can appear as three identifiers unless the product ties them to a single account, and a household sharing one login appears as one person.

Because no standard body sets the rules, each company writes its own. Facebook's 2012 prospectus counted figures from internal data with known fictitious and duplicate accounts removed, and estimated that "less than 5%" of daily users might have been counted through automatic mobile app activity rather than deliberate use. Twitter's replacement metric, introduced in February 2019, counted only users who signed in and used the service on a surface able to display ads. Reddit reports daily active uniques and includes logged-out visitors; in the third quarter of 2025, logged-out users grew 24% against 14% for logged-in users.

Daily, weekly and the stickiness ratio

MAU sits in a family of metrics. Daily active users (DAU) applies the same logic to a single day, and weekly active users (WAU) to seven days. Dividing average DAU by MAU produces a "stickiness" ratio, which describes how often the monthly audience returns.

A hypothetical example shows the arithmetic. An app with 2 million MAU that averages 500,000 DAU across the month has a DAU/MAU ratio of 25%. On average, a monthly user is active on about 7.5 of 30 days. A rival with the same 2 million MAU and 1.2 million DAU scores 60%, meaning its typical user appears on about 18 days. The two apps report identical MAU, yet the second offers an advertiser two and a half times as many daily impression opportunities.

The window matters for comparisons. In May 2026, Gemini reached 900 million monthly active users, while OpenAI had reported 900 million weekly active users for ChatGPT in February. A monthly count captures more occasional users than a weekly one, so the figures are not equal. One analyst's attempt to bridge them assumed ChatGPT's monthly audience was 1.5 times its weekly one, an assumption rather than a disclosed number.

Origin and evolution

Active-user counts spread through consumer internet companies in the 2000s as web analytics moved from counting page hits to counting people. The metric became a public benchmark with Facebook's initial public offering filing in February 2012, which reported 845 million MAU and 483 million DAU as of December 2011. Facebook passed 1 billion MAU in October 2012, and for a decade quarterly MAU was the number analysts watched first.

Twitter disclosed in October 2017 that it had overstated MAU by up to 2 million, because users of Digits, an SMS login tool for third-party apps, had been counted as Twitter users. On February 7, 2019, Twitter reported 321 million MAU for the fourth quarter of 2018, down from 326 million, and said it would stop reporting the figure in favour of monetizable daily active users (mDAU), which stood at 126 million.

Meta followed a similar path. Its family-level metrics, Family Daily Active People (DAP), estimate unique people using at least one of Facebook, Instagram, Messenger and WhatsApp. In its annual report for 2023, Meta said it would no longer report Facebook DAU, MAU, average revenue per user or Family monthly active people from the first quarter of 2024. The last Facebook figures, released on February 1, 2024, were 2.11 billion DAU and 3.07 billion MAU, against 3.19 billion DAP.

Regulators and the count

Regulators have taken an interest because the numbers move share prices and trigger legal duties. On January 30, 2020, the US Securities and Exchange Commission (SEC) issued interpretive guidance on key performance indicators in management's discussion and analysis (Release 33-10751), listing daily and monthly active users among its examples. It did not define the metrics. Instead it asked companies to disclose a clear definition, explain why the metric is useful, and disclose and recast prior periods when a calculation method changes.

The European Union went further. The Digital Services Act (DSA) requires every online platform and search engine to publish its average monthly active recipients in the EU at least every six months under Article 24(2), with the first figures due on February 17, 2023. A service averaging 45 million or more, roughly 10% of the EU population, can be designated a very large online platform and faces risk-assessment and audit duties. Recital 77 states that an active recipient "does not necessarily coincide with that of a registered user", counting anyone exposed to content, and allows providers to discount bots and scrapers where they can. Commission guidance published on February 1, 2023 added that providers need not track individuals to avoid double counting.

The result is a regulated number with self-reported inputs. On August 31, 2026, the Commission designated ChatGPT after OpenAI declared 159.1 million average monthly users in the EU, alongside Reddit at 57.2 million and Roblox at 46.6 million. The Commission publishes such figures without prejudice to any assessment of the methodology.

Why it matters for marketers

For advertisers, MAU is a ceiling on addressable audience and a denominator for price. Pinterest calculates average revenue per user (ARPU) by dividing regional revenue by average regional MAU. In the third quarter of 2025, when it reached 600 million MAU, ARPU was $7.64 in the US and Canada against $0.21 in the rest of the world, a gap of more than 36 times.

Platform growth claims also frame media plans. Snap reported 946 million MAU but 474 million DAU for the fourth quarter of 2025, with North American daily users down 6 million year on year. The monthly figure rose while the daily audience in its most valuable region shrank, a divergence MAU alone would hide.

Marketers also encounter MAU in their own businesses. Subscription apps and software vendors track it alongside churn, and lifecycle teams use activity windows to tag users as at risk or dormant.

Limitations and disputes

The central criticism is that MAU measures presence, not attention. A user who opens an app once by accident counts the same as one who spends hours in it every day. Duplicate and fake accounts inflate the total: in its 2023 annual report, Meta estimated duplicate accounts at about 10% of worldwide MAU and false accounts at about 4%.

Bots became a legal dispute in 2022. Elon Musk put his agreement to buy Twitter on hold on May 13, 2022, questioning the company's estimate that spam and fake accounts made up less than 5% of mDAU, and sought to end the deal on July 8. Twitter sued, and the acquisition closed on October 27, 2022.

Comparability is a further problem. Logged-out counts, family-level aggregation, the choice of window and averaging methods all differ, so figures from two companies rarely measure the same thing. Disputes about who counts can be decisive under the DSA: Zalando argued that only around 30 million users engaged with third-party listings, while the Commission counted 83 million across its site, and the EU General Court upheld the designation on September 3, 2025, according to PPC Land's VLOP explainer.

Not the same as

  • Daily active users: the same counting logic over one day. DAU is always lower than MAU and says more about habit.
  • Unique visitors: a web analytics or panel measure of distinct browsers or people reaching a site, often without login. USA TODAY Co. reported 158 million average monthly unique visitors in the second quarter of 2026, combining Comscore data for the US with Adobe Analytics for the UK.
  • Reach: the number of distinct people who saw an advertisement at least once in a period, a campaign metric rather than a platform metric.
  • Registered users: everyone who ever created an account, active or not, including the inactive accounts MAU is designed to exclude.

Recent developments

Meta's second-quarter 2026 results put Family DAP at 3.60 billion for June 2026, up 3% year on year, while Threads passed 500 million monthly users. Because Meta no longer publishes Facebook-only counts, outside commentators cannot confirm whether usage of the original app is rising or falling. Reddit entered the S&P 500 in August 2026 with more than 130 million daily active uniques. As of October 2026, the largest AI assistants report in different windows, and the DSA is turning self-declared EU monthly figures into the trigger for supervision.

Timeline

  • February 1, 2012: Facebook's IPO filing reports 845 million MAU and 483 million DAU as of December 2011.
  • October 2012: Facebook passes 1 billion MAU.
  • October 26, 2017: Twitter discloses it overstated MAU by up to 2 million through Digits users.
  • February 7, 2019: Twitter reports 321 million MAU and says it will switch to mDAU.
  • January 30, 2020: SEC issues guidance on key performance indicators, citing active users as an example.
  • May 13 to October 27, 2022: Musk's Twitter acquisition is paused and disputed over spam-account estimates, then closes.
  • October 27, 2022: The Digital Services Act is published in the EU's Official Journal.
  • February 1, 2023: Commission publishes Q&A on counting active recipients.
  • February 17, 2023: First DSA deadline for publishing average monthly active recipients.
  • April 25, 2023: First designations of 17 very large online platforms and 2 search engines.
  • February 1, 2024: Meta releases its final Facebook DAU and MAU figures before dropping them from the first quarter of 2024.
  • September 3, 2025: EU General Court upholds Zalando's designation in a dispute over user counting.
  • February 27, 2026: OpenAI reports 900 million weekly active ChatGPT users.
  • May 2026: Gemini reaches 900 million monthly active users.
  • August 31, 2026: ChatGPT, Reddit and Roblox are designated under the DSA on declared EU monthly figures.

Summary

Who: Consumer internet companies such as Meta, Snap, Pinterest, Reddit, OpenAI and Google report active-user figures, while investors, advertisers, the SEC and the European Commission rely on them. Product, growth and lifecycle teams use the same metric inside their own businesses.

What: A count of unique people, accounts or devices that perform a qualifying action at least once in a 30-day or calendar-month window, with definitions of identity, activity and window set by each company and, in the EU, shaped by the DSA's concept of active recipients.

When: Active-user counts spread through the consumer web in the 2000s and became a headline metric with Facebook's IPO filing in February 2012. Twitter abandoned MAU in 2019, the SEC issued KPI guidance in 2020, the DSA made EU monthly figures mandatory from February 2023, and Meta dropped Facebook MAU from 2024.

Where: In earnings releases, annual reports and DSA transparency disclosures, and in the analytics and CRM tools companies use to monitor their own products.

Why: MAU separates people who use a product from those who once registered, sizing advertising audiences and anchoring revenue-per-user calculations. Bots, duplicate accounts, inconsistent definitions and the gap between presence and engagement explain why many companies now lead with daily or engagement-based metrics instead.