Accidentally Over-contributed to 401k

[pseudoyams]

Hi everyone-
  We have been procrastinating on our taxes and just wrapping them up today. I just found out that I over-contributed to my 401k in 2018 by $354.  I started a new job on Jan 2 2018 and thought I had a clean break in terms of payroll, but there one was last partial paycheck the old employer issued that went towards 2018 income with a 401k contribution.  Shortly after moving positions I rolled over the old account into the new, and the old employer account was closed.

I contacted the current employer plan and we missed their cutoff to correct this, which was on the 5th.  They said requests wont get processed from here on out. I realize Im going to get taxed on the $354 excess when I file, but how can I correct this in the future?  Do I need to file an amendment and have the current plan withdraw the $354 or just contribute $354 less this year?

Any advice is appreciated.  Thanks!

[Miss Piggy]

I made the same mistake in 2017 due to switching employers and over-estimating. I told my current employer (the payroll department at my company, not the employer plan administrator), and they fixed it for me in 2018. There was no talk of any kind of deadline, but I likely told them in March after I did the math on all of my W-2s.

[nvmama]

I actually did this this year too.  I went over by $2.40.  Ugh.  I contacted Fidelity, where my plan is.  I had to fill out an reimbursement of excess contribution form.  It was pretty easy to do.  The hardest part was getting my hr personto sign the portion.  I'll have to pay taxes on it next year.

[pseudoyams]

Thanks for the replies. I understand it could have been corrected before April 15th, but the issue is that I contacted Schwab and they said its too late to request a correction.  Its past their deadline of being able to fulfill the request. So, there's basically no chance of correcting this before my the tax deadline.

With that, I understand Ill be taxed on the $354, but my question is - is there a way to correct this after my taxes are filed so I dont have to pay taxes again on the gains from the $354 overcontribution when I start to withdraw from my 401k?  Im 37 years old so itll be some time before that begins.  Can I correct this after April 15 and amend the return or am I stuck where its at now and just have to accept the double tax on it?

Thanks.