If my boyfriend and I bought a house together in 2024 do we file jointly or separately?

You cannot file a joint tax return unless you are legally married.   You are each single and use single as your filing status unless one of you has children ---then maybe you could file as Head of Household.

CO-OWNING A HOME

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-credits-deductions/deduct-mortgage-interest-co-owned-home/L6yLU1kKI_US_en_US?uid=lrv7xcw2

Go to Federal> Deductions and Credits> Your Home to enter mortgage interest, property taxes, and mortgage insurance that you paid in 2024   You should have a 1098 from your mortgage lender that shows this information.  Lenders send these in January/early February or you may be able to import the 1098 from the lender’s website.

Your itemized deductions have to be more than your standard deduction before you will see a change in your tax owed or tax refund.  The deductions you enter do not necessarily count “dollar for dollar;” many of them are subject to meeting  tough thresholds—medical expenses, for example, must meet a threshold that is pretty hard to reach.  The software program uses all the IRS rules that apply to the expenses you enter, and it tells you if you have enough to use your itemized deductions or if using the standard deduction is more advantageous for you.  Under the new tax laws, some deductions have been capped—there is a $10,000 limit to the itemized deductions for state, local, property and sales taxes. 

2024 STANDARD DEDUCTION AMOUNTS

SINGLE $14,600    (65 or older/legally blind + $1950)

MARRIED FILING SEPARATELY            $14,600    (65 or older/legally blind + $1550)

MARRIED FILING JOINTLY $29,200    (65 or older/legally blind + $1550)

HEAD OF HOUSEHOLD $21,900    (65 or older/legally blind + $1950)