I'm not sure what happens with child credits. I have a faint recollection that it was a big deal difference in a prior return. To be honest, I have no idea how the new tax law changes affect anything. All I know is none of those changes will help me because there are income limits. So I get no senior credit or increased SALT deduction among other things.Hi, many thanks for the detailed explanation on how to do this in TurboTax, appreciate it!
I do this every year for my son/DIL. She has large student loans so must keep her taxable income low to get a more favorable loan repayment. Unfortunately, student loan repayment penalizes those who file MFJ, hence the need to file MFS.
I use TT desktop and have used it for many years. It is relatively inexpensive if you buy on Black Friday or Cyber Monday. While I use the "what-if" form to do various comparisons, I'm not sure how accurate it would be for comparing MFS to MFJ. Maybe I'll try it myself and see how close it comes.
What I do is the following: I create an MFS tax return for each of son and DIL by inputting their data. I then take son's MFS tax return and "save as" a new return with a different name, so his data is already there. I then take that new return and change it to MFJ and add in DIL's tax info. That way I end up with two MFS returns and one MFJ return so I can compare the numbers. Of course, this gets a bit complicated because they have two kids. Filing MFS with kids and a mortgage is a bit of a hassle.
Unless you have a very peculiar situation, it is highly doubtful that MFS would give you a lower tax liability. In addition, you lose some benefits when filing MFS. You are no longer eligible to make a Roth contribution unless you do so via the backdoor route. If you have kids, I think you lose substantial child credits under MFS and it can screw up dependent care credits. And if you have a mortgage, each party has to take half the deduction and the mortgage cap is cut in half. There is no question that getting a divorce and filing single is a much better deal taxwise.
I described our situation a bit more in the post directly above, hope that clarifies our situation.
Just to clarify though, what are you referring to when you say that one can lose child tax credits with MFS? My understanding is that the child tax credit is claimable even with MFS. Is that not correct?
Please keep the forum posted on what you ultimately find out when you do your comparison as many of us will be curious and anxious to learn. I doubt there is any easy way to do a comparison without actually creating different returns. "What-If" is great if you want to see how increasing your income or Roth conversion or LTCG affects your tax liability. I am skeptical about comparing MFJ with MFS only because there are too many moving parts.
I had another thought about how to create three returns. Perhaps start with creating H&W MFJ return. In this return you will have all of the information re income and deductions. Then save this return as two other returns, naming one H MFS return and the other W MFS return. Then on each return, eliminate the info pertaining to the other person.
Then you need to pay careful attention to the kids and the deductions. Only one can claim the kids as you know. If one itemizes, then both must itemize. Then you have to carefully deal with the mortgage interest deduction. I think the loan balance is capped at $750K, but only $375K per MFS taxpayer. Having one MFS filer try to take the full mortgage deduction doesn't work. There could be a few other quirks too depending on your individual circumstances. (E.g., the dependent care plan you signed up for last January is now lost at tax time. Ouch!)
Statistics: Posted by JazzTime — Thu Jan 29, 2026 12:35 pm — Replies 7 — Views 313