Marriage Tax Calculator

For federal tax purposes your marital status on December 31 applies to the whole year, so a couple who marries in December files as married for that year. Married couples choose between filing one joint return or two separate returns. Most file jointly, and that is what this calculator compares against each person's tax as an unmarried filer.

Benefits of Filing Jointly as Married Spouses

For most couples, and especially those with unequal incomes, filing jointly lowers the total tax bill. The joint brackets for 10% through 32% are exactly twice as wide as the single brackets, so when one spouse earns much more than the other, the joint return lets part of the higher earner's income be taxed at the lower earner's unused lower rates. That is the classic marriage bonus. Joint filers also gain access to several tax breaks that are unavailable or limited for married people filing separately:

• A standard deduction of $31,500 for 2025, twice the single amount.
• Eligibility for the earned income tax credit, the American opportunity and lifetime learning education credits, and the student loan interest deduction.
• Higher income limits for contributing to a Roth IRA and for deducting traditional IRA contributions.
• The ability to make a spousal IRA contribution for a spouse with little or no earned income.
• Higher thresholds before Social Security benefits become taxable and before the child tax credit phases out.
• A $500,000 home-sale gain exclusion instead of $250,000, when both spouses meet the use test.
• Unlimited tax-free transfers of property between spouses during life and at death.

Married Filing Separately

Married couples can instead each file their own return. It usually costs more tax, because many credits are lost and the separate brackets are half the joint ones, but it can make sense when one spouse has large medical expenses (deductible only above 7.5% of AGI), is on an income-driven student loan repayment plan, or when one spouse wants to be responsible only for their own tax.

The Marriage Penalty

A marriage penalty occurs when two people pay more tax as a married couple than they would as two single filers. Under current law, the ordinary income brackets are fully doubled for joint filers only up to the 32% bracket. The 35% bracket for joint filers ends at $751,600 for 2025, while two single filers would not reach 37% until each earns more than $626,350, so high-earning couples with similar incomes can pay more after marriage.

Other parts of the code produce penalties at lower incomes. The earned income tax credit phases out at income limits that are not double the single ones, so two low-wage workers can lose some or all of the credit by marrying. The $10,000 cap on the state and local tax deduction (raised to $40,000 for 2025, with small yearly increases through 2029) is the same for married couples as for a single person, effectively halving it per spouse. The 0.9% Additional Medicare Tax starts at $250,000 of joint wages rather than $200,000 per person, and the 3.8% net investment income tax uses the same thresholds. Couples with two similar incomes and children may also see head of household status disappear.

Whether marriage helps or hurts depends on how incomes are split. Very unequal incomes almost always produce a bonus; two similar high incomes, or two low incomes with children, are the most likely to see a penalty.

Marriage penalty (or bonus) = Tax filing jointly − (Tax of spouse 1 + Tax of spouse 2) as single filers

A positive result is a penalty: the couple pays more together than apart. A negative result is a bonus.

Frequently asked questions

Sources

• IRS – Filing status
• IRS – Federal income tax rates and brackets
• IRS Publication 501 – Dependents, Standard Deduction, and Filing Information