The Residency Test

Your partner must actually live with you in your home to qualify as your dependent. They can’t maintain their own residence, not even for a week or a month. Their address must be your address throughout all 365 days of the tax year. Temporary absences are okay, however. Your partner might be hospitalized, incarcerated, or serving in the military. Maybe they’ve taken an extended vacation. That’s fine, as long as they intend to return to your home after these events—and they actually do so. Some qualifying relatives don’t actually have to live with you, but this rule is reserved for literal relatives, which your partner is not. You can’t claim your partner as a dependent for that tax year if they move in with you in March, but you can claim them in the next year if they’re still living with you on January 1, and they remain with you all through that year—assuming they meet the other qualifying rules.

Income and Support Factors

Your partner must effectively live with you because they can’t afford to live on their own, and this can’t be just an objective opinion. The IRS imposes actual income limits. They can’t earn more than $4,300 as of the 2021 tax year—the tax return you’ll file in 2022. This figure is adjusted for inflation, so it can be expected to increase periodically. It used to be equal to the amount of the personal exemption that was available each year, but the exemption itself has been reduced to zero through 2025 under the terms of the Tax Cuts and Jobs Act (TCJA). This is your partner’s gross income, not their taxable income after claiming various deductions. Certain tax-exempt sources of income, such as Supplemental Security, don’t count toward the total, but unearned income such as interest or dividends does. You can’t claim your partner as a dependent if $600 of your monthly budget is attributable to them and they contribute their limited income of $345 a month, because $345 represents more than 57% of their $600 share of your living expenses. But you can claim them if $1,000 of your budget is dedicated to their support, because now they’re paying $345, and you’re paying $655 a month, which comes out to more than 65%.

If Your Partner Is Married

Your partner must file a separate married return, not a joint return with their spouse if they’re still legally married to someone else because their divorce isn’t final yet. Neither your partner nor their spouse can owe taxes if they file separate married returns. The IRS additionally says that your relationship with your partner must be “legal” in the state where you reside. This doesn’t mean you have to get married or enter into a recognized domestic partnership, but it could be a problem if your partner is still legally married to someone else, and you live in a state where it’s illegal to cohabit with a partner who’s married to someone other than you.

A Few Other Rules

Your partner must also be a U.S. citizen, national, or resident alien, or a resident of Canada or Mexico. Of course, establishing residency in those countries would probably mean they’re not living with you full-time, so as a practical matter, they wouldn’t be your dependent. Finally, no one else can claim your partner as a dependent. The Internal Revenue Code provides that only one taxpayer can claim the same individual as a dependent per tax year.

Advantages of Having a Dependent

It used to be that you could slash $4,050 off your taxable income in the form of a personal exemption for each dependent you could claim in 2017. Then the TCJA eliminated personal exemptions from the tax code beginning in 2018. The TCJA remains in effect through 2025. You might still qualify for other tax breaks related to having a dependent, however. The credit for other dependents is worth $500 per qualifying dependent. Tax credits are particularly beneficial because, unlike tax deductions, they come directly off any tax you owe to the IRS, dollar for dollar. Deductions only reduce your taxable income.

Qualifying as Head of Household

Having a dependent can also qualify you for the advantageous head of household filing status. You’d qualify as head of household anyway if you’re already supporting a child or other dependent, but otherwise, claiming your partner as a dependent can increase your standard deduction to $18,800 as of the 2021 tax year, and $19,400 for tax year 2022. The standard deduction for single filers is $12,550 for tax year 2021 and $12,950 for tax year 2022. There are a few other rules for qualifying as a head of household in addition to having at least one dependent. Many of them mirror the same rules for claiming your partner as a dependent anyway, however:

You must pay more than 50% of your home’s expenses.Your spouse didn’t live in your house the final six months of the tax year.

This six-month rule would disqualify your partner as your dependent anyway, assuming they weren’t living with you and your spouse at the same time.

Should You Get Married?

Your standard deduction would hike even more if you and your partner were to get married and file a joint married return—up to $25,100 in the 2021 tax year and $25,900 in tax year 2022. But you’d be gaining a spouse and losing a dependent, which could cost you some of those other tax breaks available to taxpayers with dependents. It all comes down to your unique personal circumstances. If you’re on the fence about getting married, consult with a tax professional and/or an attorney to make sure you understand all the implications. You also might want some tax advice to make absolutely sure that your partner qualifies as your dependent.