Thanks to the fiscal cliff deal and the Affordable Care Act, the top 1% of taxpayers - and many in the top 3% as well - will have to pay a bigger tax bill come April 15.
That's because those laws included four key tax measures that went into effect for tax year 2013.
Who'll be hit hardest? Those who make 7-figures with substantial wage and investment income.
Households with incomes over $1 million could pay about $170,000 more on average than they did in tax year 2012, according to estimates from the Tax Policy Center.
Those making between $500,000 and $1 million would likely pay an average of $15,000 more.
Plenty of taxpayers with incomes between $200,000 and $500,000 also could be affected by some of the changes.
Here's where the increases will come from:
1. Higher top income tax rate
For those with taxable income over $400,000 ($450,000 if married), their top income tax rate is now 39.6%, up from 35% previously.
2. Higher capital gains and dividend tax rates
For those making over $400,000 ($450,000 if married), their rate on dividends and long-term capital gains is now 20%, up from 15% previously.
3. Higher Medicare taxes
For those making over $200,000 ($250,000 if married), their Medicare taxes will go up on their wages and, for the first time, their investment income will be subject to a Medicare tax as well.
On wages: They will pay another 0.9 percentage points of Medicare tax on wage income over $200,000 ($250,000 if married). That's on top of the 1.45% Medicare tax that they must pay on all their wages (or 2.9% if they're self-employed).
So, for example, a single bank executive making $500,000 in wages - which is $300,000 above the applicable threshold - would have to pay an additional $2,700 in Medicare taxes (0.9% x $300,000)
On investments: Some or all of their taxable capital gains, dividends, interest, rental income and annuities will be subject to a 3.8% Medicare tax. But just how much will be subject to tax will take some figuring. Good thing they can afford an accountant.
Here's how it would work: The 3.8% tax applies to whichever is less -- their taxable investment income or the amount that their modified adjusted gross income (AGI) exceeds the $200,000/$250,000 threshold.
Say a married couple has a modified AGI of $350,000 - which exceeds the applicable threshold by $100,000 - and investment income of $150,000. They'd owe the 3.8% surtax on the lesser of those two. So their additional tax would be $3,800 (3.8% x $100,000).
It will come as a relief to many that capital gains from a home sale up to $250,000 for an individual and $500,000 for a married couple remain tax free.
4. Limits on deductions
For those whose AGI is over $250,000 ($300,000 if married) they could see the value of their personal exemptions and certain itemized deductions reduced because Congress reinstated the so-called PEP and Pease limitations.
Personal exemptions are reduced by 2% for each $2,500 that one's AGI tops the $250,000/$300,000 threshold.