Does A 401K Contribution Reduce AGI? 
That is a great question ! I am pleased to hear you ask about your 401k , planning for your retirement is a good thing , and I wish more people were doing it . If your contributions are being made pre-tax , then yes , your Gross Income will be adjusted downward for the amount of those contributions . If they are made after-tax , then they obviously will not . I hope that helps , thanks for asking ! 