It's "pants are". Some nouns, including pants, only have a plural form and require a plural form of a verb.
It's "pants are". Some nouns, including pants, only have a plural form and require a plural verb.
Your pants are on the floor.
Your pants is on the floor.
Alternatively, you can use the expression "a pair of pants", which denotes a single entity and takes a singular form.
There is a pair of pants in the closet. (not "There are...")
Follow the same convention with other verbs, such as look, have, fit, hang, etc.
Your pants fit like a glove. (not "fits like a...")
Be also aware that we always use a plural pronoun or determiner (these, those, they, etc.) with plural nouns (like "pants").
These pants are great! Do you like them?
Below you can find a partial list of clothing-related words that only have a plural form, and consequently take "are":