If the stimulus check you're supposed to get hasn't arrived in your bank account, you may get a little more in the form of a "plus-up." However, the IRS warns that some people may not receive as much as they expect.

The IRS has already begun sending out add-up payments to process 2020 tax returns. However, even if you are entitled to a plus-up payment, the way payments are calculated does not necessarily mean you will receive an entirely new $1,400 check in the mail.

The complication stems from the fact that the first two stimulus check payments were based on 2019 tax returns. As a result, if circumstances changed during the 2020 tax year, such as the birth of a child or a decrease in income, the IRS could not take that into account until now.

Based on the new tax-related circumstances, some people will pay additional funds on top of what they already receive, and according to the IRS, there are two ways to claim it:

Those who qualify for the extra payment are those whose income in 2020 was Those who had considerably less income in 2020, married couples, taxpayers who have children and can claim additional dependents, and non-tax filers who also have new eligible dependents.

However, all of this depends on filing a 2020 tax return. Some people, such as low-income families, are not normally required to file, but if they do not file, the IRS will not send them a plus-up check. [The IRS warns that tax return adjustments can be complicated by dependents, especially since teenage dependents over age 17 were not eligible for the first two checks. In other words, if you received an additional $500 or $600 as part of the first two stimulus checks, but your child was already 17 on January 1, 2020, you would not be entitled to an adjustment because you were not eligible for the first check.

As I said, this is complicated and requires some effort to find out if you are actually eligible. Call the IRS at their phone number and check out their guide to the stimulus check calculator to find out more about your payment and eligibility.