• This tax season offers an opportunity for people who are still missing stimulus check money to claim the funds.
• However, just because you ask for the money does not necessarily mean that is the amount you will get.
• The IRS will also calculate how much you should receive. If there's a correction, they will send you a letter explaining why.

A year into the coronavirus pandemic, some Americans are still confused as to why they received less stimulus check money than they anticipated and, in some cases, no money at all.

If that's you, there's good news: A recovery rebate credit on this year's tax return will let you submit your claim for those funds.

Remember, that does not necessarily mean you will get the exact amount you think you are due.

Here's how it works: The stimulus checks issued over the last year for up to $1,200 and $600 per person essentially were advance payments of the recovery rebate credit.

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A section for claiming that credit has been added to this year's tax return forms — line 30 of Forms 1040 or 1040-SR.

On that part of the return, tax filers can start with the amount of stimulus money they already received and calculate any more funds which they are due. That can be done either through a worksheet provided with the tax form or through tax preparation software.

Once the IRS receives the return, the tax agency will also tally your recovery rebate credit, which means it may correct the amount you claim.

If there is a discrepancy, that could lead to a "slight delay" in processing the return, according to the tax agency.

However, for people who still do not understand why they received less money than they thought they were due, or no money at all, the process could help resolve the confusion.

The IRS will mail letters to filers in this situation to explain what prompted the correction.

Some reasons why the IRS might correct the credit amount include not providing a valid Social Security number or if you were claimed as a dependent on a 2020 tax return. If a dependent was age 17 or over as of Jan. 1, 2020, they will not be eligible for a payment, per the terms of the first two checks.

Math errors in the rebate calculations could also prompt a correction.

The recovery rebate credit on this year's tax return generally applies to the first two stimulus checks.

However, the IRS will potentially top up the new $1,400 payments in some circumstances, such as if your 2020 return shows your income dropped since 2019.

Filing a 2020 tax return will also enable you to receive a stimulus check if the government does not have your information on record, particularly if you do not normally file returns.

Of note, federal beneficiaries — such as those who receive Social Security, Supplemental Security Income or Railroad Retirement benefits — should get their checks automatically, even if they do not normally file returns. However, if those beneficiaries need to submit information on eligible dependents, the IRS encourages them to file a tax return.

Federal tax returns are generally due on May 17 this year.

If your income is $72,000 or less, you can file your tax return for free using the IRS Free File program.