This form calculates the well-known nanny tax.

You must collect payroll taxes on the wages of all household employees and send them to Uncle Sam. A household employee is an individual (who is not a business employee) who performs nonbusiness services for you in your home, such as child or dependent care, housecleaning, cooking and yard work.

This form is most commonly used for child or dependent care workers, but technically, if you employ any of these workers, Uncle Sam should get this form and his money.