Form 4137 - Tip Income - Social Security & Medicare Tax
If you are entering an amount in box 8 of the W-2 for Allocated Tips, this amount will transfer to Line 1 of Form 4137 for the calculation of social security and Medicare tax on the tips to be reported on Line 57 of Form 1040. The amount in box 8 is not included in box 1 wages of the W-2.
If you received other unreported tips, then this amount would also need to be entered in the Q&A for Form 4137.
To access the Q&A for Form 4137:
From within your TaxACT return (Online or Desktop) click on the Federal Q&A tab
Click on Other Income to expand the category, then click Taxes on tip income
Click Yes on the screen titled Other Income - Unreported or Allocated Tips