You may think you are discreet about your political views. But Facebook, the world’s largest social media network, has come up with its own determination of your political leanings, based on your activity on the site.

And now, it is easy to find out how Facebook has categorized you — as very liberal or very conservative, or somewhere in between.

Try this (it works best on your desktop computer):

Go to facebook.com/ads/preferences on your browser. (You may have to log in to Facebook first.)

That will bring you to a page with your ad preferences. Under the “Interests” header, click the “Lifestyle and Culture” tab.

Then look for a box titled “US Politics.” In parentheses, it will describe how Facebook has categorized you, such as liberal, moderate or conservative.

(If the “US Politics” box does not show up, click the “See more” button under the grid of boxes.)

Facebook makes a deduction about your political views based on the pages that you like — or on your political preference, if you stated one, on your profile page. If you like the page for Hillary Clinton, Facebook might categorize you as a liberal.

Even if you do not like any candidates’ pages, if most of the people who like the same pages that you do — such as Ben and Jerry’s ice cream — identify as liberal, then Facebook might classify you as one, too.

Facebook has long been collecting information on its users, but it recently revamped the ad preferences page, making it easier to view.

The information is valuable. Advertisers, including many political campaigns, pay Facebook to show their ads to specific demographic groups. The labels Facebook assigns to its users help campaigns more precisely target a particular audience.

For instance, Donald J. Trump’s presidential campaign has paid for its ads to be shown to those who Facebook has labeled politically moderate.

Campaigns can also use the groupings to show different messages to different supporters. They may want to show an ad to their hard-core supporters, for example, that is unlike an ad targeted at people just tuning in to the election.

It is not clear how aggressively Facebook is gathering political information on users outside the United States. The social network has 1.7 billion active users, including about 204 million in the United States.

Political outlook is just one of the attributes Facebook compiles on its users. Many of the others are directly commercial: whether you like television comedy shows, video games or Nascar.

To learn more about how political campaigns are targeting voters on social media, The New York Times is collecting Facebook ads from our readers with a project called AdTrack. You can take part by visiting nytimes.com and searching for “Send us the political ads.”