Per IRS Instructions for Form W-2 (Instructions for Employee - Box 10):
Box 10. This amount includes the total dependent care benefits that your employer paid to you or incurred on your behalf (including amounts from a section 125 (cafeteria) plan). Any amount over $5,000 is also included in box 1. Complete Form 2441, Child and Dependent Care Expenses, to compute any taxable and nontaxable amounts.
To enter child and dependent care expenses:
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.