Single vs. Married Taxes: How Should I File?

It's based on more than your marital status alone

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When filing your federal income taxes, you have to select from five tax filing statuses, all of which hinge on one important factor: your marital status. The main difference between filing single and filing as married for tax purposes is how your income is treated as either individual or combined, and how this figure is assessed for deductions, credits, and thresholds in the tax code.

Selecting a status is not always as simple as checking a box to say whether or not you are married. You might be single, or married filing jointly or separately. Qualifying as head of household requires that you not be married, and the qualifying widow(er) status requires that your spouse must have died within the last two tax years. There’s some overlap in the rules, so it occasionally happens that a taxpayer can technically qualify for more than one status. That’s not usually the case when it comes to filing married versus filing single, however, and here we'll break it all down.

What's the Difference Between Filing Single and Filing Married?

  Filing Single Married Filing Jointly Married Filing Separately
Marital Status Unmarried on December 31 of tax year; Divorced or legally separated on Dec. 31 of tax year; Can be head of household Married on December 31 of tax year; Cannot be head of household Married on December 31 of tax year; Cannot be head of household
Liability  Individual tax liability Joint and several liability Individual tax liability
Tax Bracket Based on income Based on combined income Based on individual income
Standard Deduction Standard deduction based on income threshold Double standard deduction Same as filing single
Credits, Thresholds, and Exemptions Variable based on income Charitable contributions favored; Medical expense thresholds disfavored Same as filing single

Marital Status: Filing Single vs. Filing Married

The all-important date here is December 31 of the tax year. Your marital status on that date determines your status for the whole year.

You’re a single filer if you were never married unless you can qualify as head of household. In no case, however, can you file a married return.

You’re also considered single if your divorce is final as of the last day of the year, or if you’re legally separated from your spouse under a court order. Simply moving into separate residences won’t impress the IRS. This would be an informal separation and the tax code says you’re still married. It can’t be a temporary court order, either, one that simply governs the situation until your divorce is finalized.

In all other circumstances, you must file a married return. A slim exception exists under the head of household rules if you haven’t lived with your spouse at any point during the last six months of the year, but you must meet some additional rules to qualify.

Otherwise, your choice is limited to filing a joint married return or a separate married return. The tax code treats you as a single filer in several ways if you file a separate return, but with some penalties. You’ll be prohibited from claiming a variety of tax credits and deductions.

Tax Liability

You and your spouse are each “jointly and severally liable” for any taxes or penalties that come due on a joint married return, and you’re also responsible for any errors or omissions on the return. If your spouse owes money to a government entity on a debt that you’re not also liable for paying, you could lose your share of any resulting tax refund if it’s intercepted. The IRS does allow you to try to make a case that you weren’t personally aware of errors or omissions, however, and you can also make a claim for your share of the refund if you weren’t responsible for the debt in question.

2021 Tax Brackets: Filing Single vs. Filing Married

The married filing jointly tax brackets are considered to be among the most favorable. You might actually find yourself in a lower tax bracket overall by filing jointly if you’re married.

For example, you and your spouse might jointly earn $130,000 annually. This puts you in the 22% tax bracket for 2020. You’d fall into the 24% bracket on an income of $130,000 if you weren’t married and filed a single return—a 2% difference, and every percentage point counts.

This difference in brackets and rates can be particularly beneficial when one spouse is self-employed and has business losses. Those losses effectively subtract from the other spouse’s earnings when they file a joint return.

Brackets break down like this for the 2021 tax year:

2021 Federal Income Tax Brackets
Marginal Tax Rate Married Filing Jointly Single
10% Up to $19,900 Up to $9,950
12% $19,901 to $81,050 $9,951 to $40,525
22% $81,051 to $172,750 $40,526 to $86,375
24% $172,751 to $329,850 $86,376 to $164,925
32% $329,851 to $418,850 $164,926 to $209,425
35% $418,851 to $628,300 $209,426 to $523,600
37% $628,301 or more $523,601 or more

Standard Deductions

The same general rule applies to standard deductions. They’re double for joint filers as of 2021: $25,100 versus $12,550 for single taxpayers, so the playing field is relatively level in this respect—with one exception, when one spouse earns very little income or none at all.

Single filers earning $130,000 can reduce their taxable incomes to $117,450, assuming they qualified for no other deductions. But joint filers earning $130,000 collectively can reduce their taxable incomes to $104,900 under the same circumstances—$130,000 less $25,100.

This would be the case even if Spouse A earned the entire $130,000, and Spouse B earned nothing at all. Spouse A can shave twice as much off her taxable income simply because she’s married.

Income ranges for tax brackets weren’t always double for joint filers. Couples who earned similar incomes and filed jointly would land in a higher bracket, which came to be known as “marriage penalty.” Congress has since fixed the brackets, equalizing them for lower-income filers.

Credits, Thresholds, and Exemptions

Of course, it’s not quite that black and white across the board. There are other tax issues to consider.

Single filers can deduct up to $3,000 in capital losses per year against taxable income, but this amount doesn’t double for married filers. They’re still limited to $3,000 jointly, or $1,500 each.

By the same token, some deductions might become more generous for single filers under certain circumstances. If a single taxpayer earning $130,000 had a lot of un-reimbursed medical expenses, she could claim an itemized deduction for the amount over $9,750 because this deduction works out to the excess over 7.5% of adjusted gross income (AGI) as of 2021.

The threshold for medical expenses is just 7.5% for the 2019, 2020, and 2021 tax years.

This threshold would double to $19,500—7.5% of $260,000—if she were married to someone who earned the same $130,000 in income and she and her spouse filed jointly. This kind of increase could quite possibly put this deduction out of reach for some filers. 

Charitable contribution deductions are limited to no more than 60% of your AGI if you donate cash. The limit drops to 30% for other types of donations. This limit is obviously more generous when you’re married, so you can double up on your incomes and file a joint return. You could give away and claim a deduction for $156,000 if you and your spouse both earned $130,000, but you could only donate $78,000 if you’re single and earned $130,000, assuming you’re that generous.

A Note on W-4 Withholdings

Your filing status isn’t just an issue at tax time. It’s critical all year, particularly if you marry or divorce in mid-year.

If you’re employed rather than self-employed, you were asked to fill out Form W-4 for your employer when you began employment. If you’re married and filing jointly, you may want to adjust your withholding to have more or less tax withheld using this form.

Form W-4 details how much income you want to have withheld from your paycheck. You may opt to have less tax withheld from your paychecks, but then you could end up owing the IRS a bundle at the end of the year because not enough was withheld to cover what you’ll ultimately owe.

Likewise, if you withhold more tax than you'll ultimately owe—because your W-4 says you’re single, not married—more of your paycheck will be withheld. You’ll get that money back as a tax refund, but you’d effectively be using the IRS as an interest-free saving account all year.

There’s little you can do about this dilemma if you’re divorced or married on December 31 because the year is over.

You should submit a new, updated W-4 whenever your marital status changes. If you marry or divorce mid-year, update your W-4 to reflect your current marital status for the new year, or as soon as possible.

The Bottom Line

The choice of whether to file single or married is usually straightforward and made for you by the definitions in the tax code. If you're married, you may need to decide whether to file jointly with your spouse or as two individual taxpayers.

However you decide to file, your income will be taxed based on the bracket it falls into, which is determined by your filing status. From there, many factors are at play. If you have an unusual tax scenario, such as a year of high medical bills, or massive charitable donations, you may want to evaluate your options to determine how different filing statuses will affect the amount of taxes you owe. Be mindful of your status throughout the year, and keep up with changes on your tax forms so that you're ready and organized when it's time to file.