What is a schedule 3 nonrefundable credit?

[Nikos]

Schedule 3 is a new tax schedule that reports non-refundable tax credits. It must be filed in order to claim certain credits.

The tax credits on the form include:

Foreign tax credit

Credit for child and dependent care expenses

Education credits 

Retirement savings contributions credit 

Residential energy credit

For more information, follow this link: https://www.irs.gov/pub/irs-pdf/f1040s3.pdf