Can I contribute more to my 401K since I am over 55 and what forms and what process do I need to follow to make the contribution before 4-15?

[jjeremiah]

I would like to know if adding 401K contributions to the additional 6k allowable for my age (over 55) will reduce my tax liability.  If allowable how do I file and what forms are needed?

[MinhT]

For 401(k) plans, the maximum contribution is $18,500 for 2018. There is a $6,000 catch-up contribution for taxpayers aged 50 or older. There is no additional catch-up contribution for taxpayers aged 55 or older (apart from the $6,000 mentioned previously).

[Zbucklyo]

You cannot make additional contributions to an employer 401k plan after the end of 2018.  If it is a solo (individual) 401k plan, you can.  There is no additional form to fill out, but the total amount contributed to a solo 401k is entered through Business Deductions and Credits during the interview for your business.