To compare Joint to MFS. If you are using the Online version, do NOT change anything on your return. You would have to start with a new account and do a test return. You don't have to pay unless you want to print it out. So you might need 3 accounts, one for Joint and two MFS, one for each spouse.
How to Compare Joint to Married Filing Separately
How to start another return in the Online version
It would be better to use the Desktop CD/Download program. It can do unlimited returns and has a What If worksheet to compare them and many other advantages over the online version.
You can buy the Desktop CD/Download program here
Here's some things to consider about filing separately……
In the first place you each have to file a separate return, so that's two returns. And if you are using the Online version that means using 2 accounts and paying the fees twice. The Desktop CD/Download program would be better to use.
Many people think they come out better when filing Married Filing Separate but they are probably doing it wrong. If one person itemizes deductions on Schedule A then the other one must itemize too, even if it's less than the standard deduction, even if it is ZERO! And if you are in a Community Property state it can be complicated to figure out.
And there are several credits you can't take when filing separately, like the
EITC Earned Income Tax Credit
Child Care Credit
Educational Deductions and Credits
And contributions to IRA and ROTH IRA are limited when you file MFS.
Also if you file Married Filing Separately up to 85`% of your Social Security becomes taxable right away even with zero other income.
See …….
Married filing Separate in Community Property States