A married couple always has the option of filing separately. To file jointly, both must agree to it. However, it is usually not advantageous.
Although there is no one answer since every situation is different, generally filing jointly will give you a bigger refund or less taxes due. When you file separately, your tax rate is higher and you won't be able to claim:
- Student loan interest deduction
- Education benefits
- Earned Income Credit (EIC)
- Child and Dependent Care Credit (usually)
- Adoption Credit (usually)
- The same benefit married filing jointly couples get for personal exemptions, itemized deductions, the Child Tax Credit, and capital losses (all of these deductions are reduced by half)
- Itemized deductions if your spouse has already claimed the standard deduction, or the other way around.
On top of that, if you live in the community property states of Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, or Wisconsin, you have to deal with community property allocations and adjustments, which adds extra work and complexity to your tax preparation chores.
Tip: Only taxpayers who were still legally married as of December 31, 2017 are able to file as marrieds, whether jointly or separately.