What are some real examples of marriage tax penalties?

Can anyone share examples where two single people would pay less in taxes than if they filed as married? I know about the $10k SALT cap, but are there other cases like that?

The NIIT threshold is $200k for singles but only $250k for married couples filing jointly.

Miller said:
The NIIT threshold is $200k for singles but only $250k for married couples filing jointly.

It’s crazy that they only add $50k for married couples.

Miller said:
The NIIT threshold is $200k for singles but only $250k for married couples filing jointly.

What’s NIIT?

Casey said:

Miller said:
The NIIT threshold is $200k for singles but only $250k for married couples filing jointly.

What’s NIIT?

Net investment income tax. It’s a 3.8% tax on the smaller of your total investment income or the amount your Modified Adjusted Gross Income exceeds those thresholds.

Tax brackets are a big issue for high earners. Most brackets double when you’re married (e.g., 10% is $12k for singles and $24k for couples), but the 37% bracket only increases from $610k to $730k. If both people make $610k, they’d pay a lot more in taxes as a couple.

@Briar
I think the difference maxes out around $10k under the current rules. Before that, it was as high as $35k.

@Briar
If you’re married, do you have to file jointly, or can you still file separately?

Lior said:
@Briar
If you’re married, do you have to file jointly, or can you still file separately?

There’s an option to file as married filing separately, but it almost always results in more taxes than filing jointly. In this case, it wouldn’t help because married filing separately usually splits the joint amounts.

@Briar
So filing separately is basically the same as filing jointly but with two tax returns instead of one?

If two single people each own a primary home, they can deduct mortgage interest on up to $1.5 million in combined loans. If they’re married, that limit drops to $750k.

California’s mental health tax is another example. It’s a 1% tax on income over $1 million, whether you file as single or married.

Casey said:
California’s mental health tax is another example. It’s a 1% tax on income over $1 million, whether you file as single or married.

California has a similar tax. Technically, you could file as married filing separately, but you’d have to do it for both federal and state returns.

@Briar
Wait, California has a tax similar to… California?

Federal tax brackets double for married couples up to the 35% bracket. Once household income is over $750k, two high earners often pay more married than single.

One of the biggest penalties I see is for unmarried parents. If they have two or more kids, they can both qualify for the Earned Income Credit separately. But as a married couple, their combined income might make them ineligible.

@Vic
Plus, they could each file as head of household, which has a standard deduction that’s almost as high as married filing jointly.

For context, a study in 2018 found that 43% of married filers paid more because they were married, while the same percentage paid less. On average, the tax bonus was larger than the penalty, though.

Being able to file as head of household instead of single is a big one.

Couples who make roughly the same amount are most likely to be penalized. Common triggers are the highest tax brackets, Medicare surcharges, and situations where itemized deductions don’t double like the standard deduction does.