2021 Child Tax Credit calculator: How much could you receive?

The vast majority of American families with children will automatically receive up to $300 per month, per child, beginning Thursday, the IRS and Treasury Department have announced.

The IRS said families who qualify for the Child Tax Credit, which was expanded as part of President Joe Biden's $1.9 trillion American Rescue Plan, will receive monthly payments without taking any further action. Initial eligibility will be based on 2019 or 2020 tax returns.

The changes increased the child tax credit from $2,000 to $3,000 for children over 6, and to $3,600 for children under 6.

According to the IRS: "For tax year 2021, the Child Tax Credit is increased from $2,000 per qualifying child to: $3,600 for children ages 5 and under at the end of 2021; and $3,000 for children ages 6 through 17 at the end of 2021."

In a nutshell: Families making less than $150,000 a year and single parents making less than $112,500 are now eligible for a credit of up to $3,600 per child. Payments will be going out to 39 million households, according to the IRS.

The IRS also added on its website: "The $500 nonrefundable Credit for Other Dependents amount has not changed."

Biden will mark the rollout of checks and direct deposits from the child tax credit with a White House event featuring Americans who will benefit.

"We have seen projections that the child tax credit, the implementation or the extension of child tax credit could reduce -- could cut child poverty in half," press secretary Jen Psaki said Wednesday. "And this is just extra money that's going into people's bank accounts who need help the most. So, the president felt it was important to elevate this issue, to make sure people understand this is a benefit that will help them as we still work to recover from the pandemic and the economic downturn."

In a June 21 statement, the president called the program the "largest-ever child tax credit."

"For parents working to make ends meet and raise their children with greater security, dignity, and opportunity, help is here," Biden said.

The Biden administration also launched a website with details about the tax credit.

The benefits will be paid monthly, according to the IRS. People can register for the program even if they did not fully file taxes.

Set to expire after a year, Biden has proposed extending the program through 2025.

In the meantime, this calculator from ABC News' data journalism team tells you how much you may receive from the Child Tax Credit program using the guidelines spelled out in the bill based on your most recent tax form. The information you enter below will not be stored or saved in any way.

ABC News' Shannon Crawford, Karen Travers and Samara Lynn contributed to this report.