Married couples can experience a 'marriage bonus' (paying less tax than two singles) or a 'marriage penalty' (paying more). Federally, most couples with one earner benefit significantly from joint filing. Dual-income couples where both partners earn similar high incomes face a marriage penalty. Several states with their own bracket structures compound or reduce the federal effect.
At a glance
Key Facts
Standard Deduction MFJ (2026)
$32,200 (vs $16,100 single — exactly double)
Federal Marriage Penalty Zone
37% bracket kicks in at $768,700 MFJ (2026, IRS Rev. Proc. 2025-32) — less than 2× the single threshold, so marriage penalty exists for dual high-income couples
Biggest Marriage Bonus Scenario
One earner household — non-working spouse doubles bracket width for no extra income
Biggest Marriage Penalty
Two earners both in top 37% bracket; also: NIIT, AMT thresholds
States with Marriage Penalty
California, New Jersey, Maryland — MFJ brackets not 2× single brackets at top
Marriage Bonus States
States with wide MFJ brackets or no income tax (FL, TX, etc.)
Introduction
The marriage bonus or penalty arises from how tax brackets are structured for married filing jointly (MFJ) versus single filers. When the MFJ brackets are exactly double the single brackets (which they are for most federal brackets), there is neither bonus nor penalty. When MFJ brackets are less than double the single brackets — as at the top of the federal schedule — a penalty applies for dual high-income couples.
This guide explains the 2026 federal marriage penalty/bonus, which states have the most severe penalties, and real examples showing when filing jointly saves money versus when it costs more.
Section 01
How the Marriage Bonus Works
When one spouse earns significantly more than the other, married filing jointly almost always produces a lower tax bill than two separate single returns:
Example: One-Earner Couple
Spouse A earns $120,000; Spouse B earns $0. As single: Spouse A's taxable income is $103,900 after the $16,100 standard deduction, which reaches into the 22% bracket. As MFJ: taxable income is $87,800 after the $32,200 standard deduction, entirely inside the 10% and 12% brackets — the 12% bracket extends to $100,800 of taxable income for MFJ (vs $50,400 single). The couple saves approximately $7,500 in federal income tax versus filing as two singles (wages only, standard deduction).
Example: Unequal Income Couple
Spouse A earns $150,000; Spouse B earns $40,000. As two singles: A pays ~$24,700 federal; B pays ~$2,600 federal = ~$27,400 combined. As MFJ ($190,000 total): approximately $24,100 federal. Marriage bonus: ~$3,200. The bonus shrinks as incomes converge.
Standard Deduction Benefit
The MFJ standard deduction ($32,200 in 2026) is exactly double the single deduction ($16,100). For a couple where neither itemises, the MFJ standard deduction provides the same proportional deduction as two single returns — no bonus or penalty here.
Section 02
How the Marriage Penalty Works
When both spouses earn similar high incomes, married filing jointly can cost more than filing as two singles:
Example: Dual High-Income Couple
Both spouses earn $600,000 each ($1,200,000 combined). As two singles: each has taxable income of $583,900 after the $16,100 standard deduction, below the 37% bracket ($640,600 for single filers in 2026). As MFJ: taxable income of $1,167,800 after the $32,200 deduction reaches the 37% bracket, which starts at $768,700 for MFJ. Penalty: a portion of income is pushed into 37% that would not have been as singles. Estimated penalty: approximately $8,000/year (wages only, standard deduction). Two equal earners with $400,000 each ($800,000 combined) see no federal bracket penalty at all, because the MFJ brackets up to the 35% bracket are exactly double the single brackets.
NIIT Marriage Penalty
The 3.8% Net Investment Income Tax applies above $200,000 (single) but only $250,000 (MFJ) — not $400,000 as you might expect. This means dual-earner couples with investment income face a larger share of NIIT than two singles earning the same total.
AMT Marriage Penalty
The Alternative Minimum Tax exemption for MFJ ($140,200 in 2026) is less than 2× the single exemption ($90,100 × 2 = $180,200). Dual-income AMT-exposed couples pay more.
Section 03
State-Level Marriage Penalty
States create their own penalties when MFJ brackets are narrower than double the single brackets:
Worst Marriage Penalty States
California: The 9.3% bracket starts at $66,295 single but $132,590 MFJ (exactly double — no penalty there). However, the 13.3% surcharge threshold for MFJ ($1M) is the same as single ($1M for married) — creating a penalty for high earners.
New Jersey: NJ's bracket widths for MFJ are not proportional to single brackets at top rates, creating meaningful penalties for dual-income high earners.
Maryland: County income tax is levied per person on combined income without full doubling of brackets in some bands.
Iowa (historically): Iowa had one of the worst marriage penalties in the US; recent flat tax reform has reduced this significantly.
States with No Marriage Penalty
States with a single flat rate (Colorado 4.4%, Illinois 4.95%, Arizona 2.5%): MFJ and single face the same percentage, so no structural penalty.
States with no income tax (FL, TX, etc.): no income tax penalty possible.
States with MFJ brackets exactly doubling single brackets at all levels.
Section 04
Should You File Jointly or Separately?
In most cases, married filing jointly (MFJ) is better — or at worst neutral. Married filing separately (MFS) is generally worse because:
Student loan interest deduction: disallowed for MFS
Child and Dependent Care Credit: disallowed or reduced for MFS
Earned Income Credit: disallowed for MFS
IRA deduction (if covered by workplace plan): significantly limited for MFS
Capital loss deduction: $1,500 limit (vs $3,000 for MFJ)
IRMAA Medicare surcharges: MFS face more aggressive premium increases
When MFS Can Help
Income-driven repayment plans: If one spouse has large student loans on IDR, their monthly payment is based on individual income under SAVE/PAYE plans. Some couples save more on loan repayment (lower monthly payment) by filing separately than they lose in tax — this requires calculation.
Injured spouse claims: If one spouse has back taxes, unpaid child support, or defaulted student loans that would seize a joint refund.
Legal separation or divorce proceedings: may want to maintain separate filings.
Marriage tax planning — joint vs separate filing analysis, income-splitting strategies, student loan IDR calculations, and state-level impact — is complex and personal. Get matched with a CPA who can model your specific numbers.
⚠ Not for simple single-state returns. Free filing is fine for straightforward W-2 situations.
It depends on your income and your spouse's income. One-earner couples almost always pay less tax after marriage (marriage bonus). The single-earner benefit is largest when one spouse earns significantly more than the other. Dual-income couples where both earn similar moderate incomes may see minimal change. Dual high-income couples where both earn above $400,000 may pay more (marriage penalty). On balance, the TCJA 2017 reduced marriage penalties at most income levels — most couples either save or pay the same amount by filing jointly.
Q
How much does a married couple save on federal taxes compared to two singles?
It varies by income combination. Rule of thumb examples: (1) One earner at $80,000, spouse $0: saves approximately $3,500 per year versus two singles. (2) Two earners at $60,000 each ($120,000 combined): approximately $0 — neutral. (3) One earner $200,000, spouse $30,000: saves approximately $5,200. (4) Both earners at $300,000 ($600,000 combined): approximately $0 — no federal penalty. (5) Both earners at $500,000: penalty of approximately $4,000. These rule-of-thumb figures use the 2026 federal brackets, wages only and the standard deduction. The calculator on our homepage can model your specific combination.
Q
Which state has the worst marriage tax penalty?
Historically, states like New Jersey and California have had significant marriage penalties for dual high-income couples. New Jersey's top 10.75% rate and bracket structure creates meaningful marriage penalties. California's 13.3% surcharge for income above $1M applies at $1M for married couples rather than $2M — identical to the single threshold at the top — creating a dollar-for-dollar penalty at top incomes. Iowa previously had one of the worst penalties but has moved to a flat tax. Overall, high-tax states with multiple income brackets and top rates that don't scale proportionally with MFJ status create the most severe marriage penalties.
Disclaimer:This guide provides general information about marriage and joint filing tax implications for educational purposes. Tax rules change frequently. Examples are simplified and may not reflect your specific situation. This is not tax advice. Consult a qualified CPA.