Monthly tracked users (MTUs) billing guide

  • Updated

Amplitude customers on Scholarship, Starter, and Plus plans are billed according to monthly tracked user (MTU) count. This option is also available to customers on Growth and Enterprise plans. 

An MTU is a unique user who triggers one or more events within a calendar month. This can be either an anonymous user (which Amplitude will track via device ID) or an identified user (tracked by user ID). If a user appears in two or more projects, they will still be counted as a single MTU.

Amplitude will track any anonymous users as distinct MTUs, even if they have previously visited while logged in. If an anonymous user subsequently logs into the site, all events triggered by the user while they were anonymous will be merged under their user ID, and will count as a single MTU.

Amplitude calculates MTU usage daily, with one additional, final calculation after the end of the calendar month to accommodate any late-arriving events. At that point, the MTU count is no longer updated to reflect subsequent user merges caused by identify calls on anonymous users. 

Your MTU count will not increase due to user mapping, identify calls, or group identifies.

MTU-based pricing is available for all Amplitude plans. Customers who use sampling are not eligible for MTU-based pricing.

Track your MTUs

The first step in setting up MTU tracking is to understand how Amplitude tracks unique users. The best way to ensure accurate counting of MTUs is to maintain a one-to-one correlation between user IDs and actual users.

NOTE: If you're using test data and generating fictitious user IDs for testing purposes, each of these test users will also be included in your MTU count.

Estimate your MTUs

If you haven't implemented tracking yet, you can use your monthly active user (MAU) count to estimate your current MTU usage. These counts should be similar, assuming they account for anonymous visitors identically.

View your MTU usage

To view your MTU usage, navigate to Settings > Plans & Billing. MTU statistics will be visible in their own panel.


NOTE: MTU counts are not available for every plan type.

In some cases, a single user may be counted multiple times when totaling MTUs. This can happen when a user is logged in, but then later opens the app anonymously on a different device or platform. Because there is no way to connect these two users, they will register as distinct MTUs unless the user eventually logs in on all devices. At that point, Amplitude will merge their profiles into a single user.

It can also happen if a user has two unlinked user IDs and uses both of them in a single month.

There are also instances where a user’s actions can result in a reduced MTU count. If a user interacts with your app anonymously and then later logs into their account on that same device, the anonymous usage will be merged with the logged-in usage, resulting in a single MTU.

NOTE: MTU billing is based on UTC time.

See this post in the Amplitude Community to learn more about investigating your organization's MTU usage.

Discrepancies with counts provided by other tools

No two tools work exactly the same way, or under the exact same conditions. Most ingest and process data differently, which will naturally generate different results. Additionally, your MTU count could differ from the results generated by running a query of user count within Amplitude due to the way MTUs are calculated.

If you believe there is an error in your MTU count, contact Amplitude support.

MTU limits

MTU limits are defined by the plan your organization is on, or the MTU volume you purchased. Amplitude will determine whether any overage fees are owed based on:

  • Your overall MTU volume, and
  • Your events per MTU volume

These are each calculated on the last day of each calendar month. Exceeding either limit can result in overage charges. Amplitude will alert you when you are approaching your limit so you can take steps to avoid exceeding it.

Exceeding your plan’s allowed MTU volume

Exceeding your plan limits or purchased MTU limit will result in charges for all excess MTUs recorded. 

For example, if you purchase n MTUs, and Amplitude records n+m MTUs at the end of the month, you will be charged for m additional MTUs.

Exceeding your plan’s events per MTU limit

Regardless of the plan you’re on, you will also be subject to a cap on events per MTU. This is calculated cumulatively. 

For example, if you purchased n MTUs and are expected to have x events per user, when your event volume k exceeds n(x), you could be charged for the difference based on the formula

(k - n(x)) / x = number of excess MTUs

Exceeding limits on a free plan

If you're a non-paying customer, your account will be blocked once you've exceeded your MTU monthly limit three times. You will no longer be able to access any of your charts and dashboards (you will still have access to certain admin functions, like the User API, so you can meet your compliance obligations). Amplitude will continue to ingest data up to and over your limit; however, unless you upgrade to a paid plan, you will not be able to access it. If you continue to exceed your monthly limit without upgrading to a paid plan, your account will be deleted six months after it was first blocked.

Unexpected usage spikes

Large and sudden increases in MTUs are almost always tied to spikes in usage of your product. If your company recently launched a new marketing campaign, a significant product update, or a change to your instrumentation, that may be the most likely explanation.

MTUs may also increase unexpectedly when you add new event sources that result in either more users, or more events for users active in third-party tools but not necessarily in your product (for example, adding an email platform as a data source).

If you believe your MTUs have spiked in error, contact Amplitude support.

How Amplitude counts backfilled events

When backdated events for previous months are added, Amplitude will add one MTU for each month in which a distinct user appears.

MTU usage calculations are based on the month an event is added to Amplitude. If you were to backfill data from previous months in February, for example, Amplitude will count all this backfilled usage against February’s MTU quota.

Similarly, determining whether a user is unique or not also hinges on the month the event was triggered. For example, if Amplitude records three events for a single user, with one dated today, a second dated one month ago, and a third dated two months ago, the count will be one unique MTU, counted in this month.

Because of this, backfilling data is a common cause of spikes in MTU usage.

Drop filters and MTUs 

When you use a drop filter, Amplitude will exclude a set of ingested events from your chart, based on the criteria you set. These events are not returned by your query, but they do still exist: Amplitude does not delete them. Because of this, the number of uniques you see on a drop-filtered chart in Amplitude Analytics may not match the number of uniques on the MTU chart in your billing report.