The marriage penalty and bonus in the brackets

How it works

For most brackets the married joint income lines are exactly twice the single lines, so two equal earners pay the same combined tax either way. The top bracket's married line is less than twice the single line, so two high earners together can cross into it sooner than they would alone. Several other lines are not doubled at all: the net investment income tax threshold for a married couple, the cap on state and local tax deductions, and the earned income credit phase out, so two earners can lose a credit or pay a surcharge that neither owed alone. The bonus runs the other way. When one spouse earns most of the income, the joint brackets let that income spread across two sets of lower rates and use the full married standard deduction of this year's official standard deduction married (not yet verified here; see the official source below).

What it gives

A couple with one main earner usually owes less tax together than that earner owed alone.

A joint return opens the full married standard deduction even if one spouse earned nothing.

Spousal IRA rules let a nonworking spouse contribute based on the other's earnings.

What it costs, or where the catch is

Two similar high earners can land in a higher bracket together than either did as a single.

Several income lines for credits and surtaxes are not doubled for married filers.

Filing separately does not undo the penalty, because the separate brackets are half the joint ones.

A worked example

Ravi earns $190,000 and his wife Pilar earns $185,000. Together, $375,000 of income crosses the married line for the net investment income tax, which is not twice the single line, so their $12,000 of dividends now draws a 3.8 percent surcharge of $456, since $12,000 times 0.038 is $456. Their friends Gus and Ines, where Gus earns $120,000 and Ines is in school, owe about $3,000 less as a couple than Gus did as a single.

Where it goes wrong

The common surprise is two earners who each had the right withholding as singles and owe a large balance in April after marrying, because neither paycheck knew about the other.

Who confirms it for you

For your own numbers, a CPA or enrolled agent. This page explains how the rule works for people in general; it does not know your situation and does not tell you what to do.

The official source

IRS Publication 17, Your Federal Income Tax. Every figure that changes by year comes from the site's rules table, which the watcher checks against the official page on a schedule; where a figure is not yet verified, this page says so instead of printing a number.