I just paid Fed tax into 2018 not 2019. Will it roll into 2019?

[xmasbaby0]

What exactly do you mean by "paid Fed tax into 2018"?  What exactly did you do?  How did you pay? By what means?

[BalloonArtist]

using an on-line 1040 payment center, I paid what I thought I would owe for self-employment income.  I clicked the 2018 box, not the 2019 tax box.  My 2018 taxes are closed and paid - nothing owed

[rjs]

The payment will not "roll" into 2019. You now have an overpayment for 2018. Call the IRS at 800-829-1040 and ask them to either move it to 2019 or send you a refund of the mistaken overpayment.