If you and your spouse are filing MFS and sharing the itemized deductions then you can each enter 50% of the mortgage interest. Split the deductions up in whatever way you agree upon as long as no more than 100% is entered between the two returns...unless you are in a community property state where it gets a lot trickier.
Why are you filing separate returns---usually the worst way to file?
If you were legally married at the end of 2025 your filing choices are married filing jointly or married filing separately when you prepare your 2025 return.
Married Filing Jointly is usually better, even if one spouse had little or no income. When you file a joint return, you and your spouse will get the married filing jointly standard deduction of $31,500 (+ $1600 for each spouse 65 or older) for 2025. You are eligible for more credits including education credits, earned income credit, child and dependent care credit, and a larger income limit to receive the child tax credit.
If you choose to file married filing separately, both spouses have to file the same way—either you both itemize or you both use standard deduction. Your tax rate will be higher than on a joint return.
Some of the disadvantages of filing separately include:
You cannot get earned income credit,
You cannot get education credits or deductions for student loan interest.
You cannot get the childcare credit
You have a lower amount of income on which to base the refundable additional child tax credit
85% of your Social Security benefits will be taxable even with no other income
The amount you can contribute to a retirement account will be limited.
Capital loss deduction is less than if you file jointly
You cannot get the $6000 senior deduction
You cannot get the deductions for overtime or tips
If you live in a community property state, you will be required to provide additional information regarding your spouse’s income. ( Community property states: AZ, CA, ID, LA, NV, NM, TX, WA, WI) and your returns become very complicated.
If you are using online TurboTax to prepare your returns, you will need to prepare two separate returns and pay twice since with online, you get one return per fee.
https://turbotax.intuit.com/tax-tips/marriage/should-you-and-your-spouse-file-taxes-jointly-or-separ...
https://ttlc.intuit.com/turbotax-support/en-us/help-article/income/getting-married-mean-taxes/L2Rgma...
https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/married-filing-separately-commu...
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
