State tax filing

In answering your question, I’m assuming you are a New Jersey resident claiming credit for Philadelphia wage tax on your NJ resident tax return.

TurboTax does not automatically calculate the credit for Philly wage tax because it is a city tax.

You add this tax yourself.

Here's how to enter the credit:

1. In New Jersey continue until you reach Credit for “Taxes Paid to Another State”
2. Tap Work on Credit
3. On “Other State Information” select Pennsylvania
4. On “Pennsylvania Credit” select Check this box if you are taking this credit because you paid Philadelphia Income Tax. Then select No.
5. On “Philadelphia Tax Credit” say Yes.
6. On “Tell us about the money you earned in Philadelphia,” enter your double-tax income and tax paid to Philadelphia

Philadelphia wages are generally higher than New Jersey wages because Philly taxes 401(k) contributions. 

See the calculation on page 11 and 12 of Credit for Income Taxes Paid to Other Jurisdictions.