Stimulus check formula deciphered: This is why you got the payment size you did

If you’re not sure about how the IRS calculates the size of your second stimulus check, now’s the time to find out. The agency uses a pretty complicated formula (it was hard-baked into the stimulus bill, in fact) that starts with your taxes. If you’re one of the tens of millions of people eligible for a second stimulus payment, your second check total relies on equations that involve your AGI and how many dependents you can claim.

That may be the “simple” answer to the stimulus check question, but it isn’t the complete picture. Another layer beneath that is a formula that’s actually written into the language of December’s COVID-19 stimulus bill. This equation is what decided how big a stimulus check the US Treasury will — or has — cut in your name.

What’s interesting and important about this second stimulus check is that it uses the same equation as the first one. Due in part to the $600 income limit with the new check, some people won’t be eligible this time around, simply because of the way the formula works. Others may still qualify, but for a smaller portion of the stimulus money than people who meet the exact same eligibility requirements. (By the way, here’s what’s happening with a third stimulus check for $2,000 and what could make it into the next stimulus package in 2021.) This story was recently updated.

How the IRS calculates your stimulus check total: Key detail

The two major variables being plugged into the equation are your adjusted gross income you put on your 2019 federal tax returns into a formula, and the number of eligible child dependents you claim. If the result is under a maximum limit, you will receive at least some stimulus check money. If the number is above it, you won’t receive any. (If you don’t typically file taxes, here’s what you need to know.)

There’s a sliding scale involved. As with the first check, if your adjusted gross income, or AGI, is less than $75,000 as a single taxpayer (that means no kids), you’ll receive the entire second stimulus check total of $600. If you made more than that, the size of your check would diminish until it hits the income limit, after which point you’d be ineligible.

This is the same equation that the IRS used for the first, $1,200 stimulus check. But the fact that this check is $600 actually lowers the maximum income limit you could hit, which means that more people will reach that limit sooner. A $600 flat payment for children 16 and younger could help mitigate your overall total (more below, it gets complex). 

This chart helps illustrate the income limits and the difference between the first and second stimulus checks.

Stimulus check income limits ($600 and $1,200 checks)

	AGI to receive full amount (Both stimulus checks)	Second stimulus check upper income limit (AGI)	First stimulus check upper income limit (AGI)	Difference between upper limits	Percentage difference between upper limits
Single tax filer	Under $75,000	$87,000	$99,000	$12,000	14%
Head of household	Under $112,500	$124,500	$146,000	$21,500	17%
Married, filing jointly	Under $150,00	$174,000	$198,000	$24,000	14%

How does it work when you add $600 for your kids?

This is where the calculations get really interesting. The numbers in the chart above don’t include the $600 flat rate for child dependents in the second stimulus check (this is up from $500 with the first stimulus check). There’s no cap on the number of child dependents that count toward your total check, as long as they’re younger than 17 years old. 

The IRS’ equation begins with the largest amount you’d be eligible to receive ($600 per single taxpayer or $1,200 for joint filers), and adds $600 for each qualifying child. Then it reduces the total possible sum according to your AGI.

It’s a little like starting a test with a perfect 100 point score and subtracting every point you “miss,” rather than starting with zero points and adding them all up at the end of the test.

But in this case, the dependents you name can start you at a higher value, say 110 points in our classroom example. So by the time you subtract “points,” you may still get more than people who don’t have dependents — even if your AGI is above the maximum cap. The more child dependents you have, the higher your starting value, and the higher your ending value, too.

That’s why it’s possible you could be out of range for a payment based on your AGI, but still receive a partial payment on the strength of your eligible dependents. Still confused? We don’t blame you. You can experiment with ranges in our second stimulus check calculator and see below for more sums.

See the stimulus check formula in action here

We want to show you the calculation at work, and how the math changes for people who claim dependents. 

Remember that with the second check, an individual can qualify for a stimulus check of up to $600, a married couple who file taxes jointly can get up to $1,200 — and there’s an extra $600 per qualified child dependent. Note that a head of household is someone who files taxes individually and has at least one dependent. People who are considered single filers claim no dependents on their taxes, only themselves, which is why this group isn’t explicitly included in the chart below. 

These figures are based on the rules set out for the second stimulus check, worked out using CNET’s stimulus check calculator. They’re best considered estimates only, since secondary qualifications that could determine your final sum. If the amount below looks higher than what you receive, though, you may need to investigate a catch-up payment from the IRS.

Stimulus check calculations with dependents ($600 second check)

	Head of household	Married couple, filing jointly
Estimated total with:
AGI of $40,000 and 0 dependents	$600 for single taxpayer with no children	$1,200
AGI of $115,000 and 0 dependents	Single filers not eligible	$1,200
AGI of $190,000 and 0 dependents	Single filers not eligible	Not eligible
AGI of $40,000 and 1 dependent	$1,200	$1,800
AGI of $115,000 and 1 dependent	$1,070	$1,800
AGI of $190,000 and 1 dependent	Not eligible	Not eligible
AGI of $40,000 and 2 dependents	$1,800	$2,400
AGI of $115,000 and 2 dependents	$1,675	$2,400
AGI of $190,000 and 2 dependents	Not eligible	$400

How will a third stimulus check work?

There’s already talk of another stimulus bill in 2021 that could yield a third stimulus check. Some are calling for it to be as large as $2,000 per eligible adult. If that were to happen, the pattern of the first two checks indicates that for the sake of simplicity, a future bill could once again direct the IRS to use the same formula. 

If a future check were larger than the $1,200 from the first stimulus payment, you could expect the income cap to rise, making more people eligible for a higher sum of money overall.

It’s possible we could also see another bid to expand the definition of a dependent, such as the Democrat-backed Heroes Act does. (This isn’t law.) A move in this direction would also make families eligible to receive money on behalf of college students and older live-in relatives. 

Both hypothetical changes would potentially increase the family’s overall pool. Remember, the bigger the sum a family starts with, the bigger the check they are likely to receive after the IRS makes its deductions based on your AGI. 

For more information, here are the top things to know about stimulus checks. And see how SSDI recipients and checks, older adults and retirees and people who aren’t US citizens or Americans who don’t live in the US can also qualify.