The payments were approved as part of the Democrats' $1.9 trillion stimulus package that President Joe Biden signed into law in March. The first installment totaled $15 billion.
The infusions may offer the greatest benefit to low-income families, cutting child poverty nearly in half -- but the extra cash will also go to better-off American families.
RELATED: Child Tax Credit Update Portal | Internal Revenue Service
Here are four things you need to know about the expanded child tax credit:
The full enhanced credit will be available for heads of households earning $112,500 and joint filers making up to $150,000 a year, after which it begins to phase out.
For many families, the credit then plateaus at $2,000 per child and starts to phase out for single parents earning more than $200,000 or for married couples with incomes above $400,000.
More low-income parents will also become eligible for the child tax credit because the relief package makes it fully refundable. It had been only partially refundable -- leaving more than 26 million children unable to get the full credit because their families' incomes were too low, according to Treasury Department estimates.
RELATED: New child tax credit payments start this week
Parents who aren't citizens can receive the payments for their citizen children as long as they have individual taxpayer identification numbers (ITIN) and their children have Social Security numbers.
Families can check their eligibility through this IRS website.
The expanded credit, however, is only in place for 2021, though Democrats hope to extend it.
Child tax credit calculator
Use the calculator below to find out how much you may get as part of the new child tax credit. Your information will not be stored in any way.
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How much will I get?
That depends on your household income and family size.
Eligible families can receive a total of up to $3,600 for each child under 6 and up to $3,000 for each one age 6 to 17 for 2021. That's an increase from the regular child tax credit of up to $2,000 for each child up to age 17.
When will I see the money?
Parents will receive half their credit -- up to $300 a month for each child under age 6 and up to $250 for each one ages 6 to 17 -- on a monthly basis from now through the rest of the year. The payments will be made on the 15th of each month, unless it falls on a weekend or holiday.
They can claim the other half when they file their 2021 taxes next year.
Parents can check if they are enrolled to receive the advance payments at an IRS portal. They can also use it to provide or update their bank account information, which will take effect starting with the August payment.
Those who don't receive their monthly payments until later in the year will still get half the credit in 2021.
Families who want to receive the payment as a lump sum can opt out of the monthly installments at the portal.
Do I have to do anything to get it?
The vast majority of families -- roughly 39 million households covering 88% of children -- will get the credit automatically because they have filed 2019 or 2020 returns claiming the credit.
The IRS will also send the payments to Americans who previously used its non-filer portal to register for the stimulus checks.
More than 35 million families were already sent the payments, while about a million have opted to take the funds as a lump sum, an administration official said Wednesday. The others have filed for extensions or have issues with their returns.
Parents of nearly 60 million children will receive the monthly payments through direct deposit, paper checks or debit cards, according to the agency. Some 86% of payments will be sent via direct deposit.
But families who haven't filed tax returns recently or used the non-filer tool must take action. They can use another IRS portal to register to receive the enhanced child tax credit. The sign-up tool allows users to provide the necessary information about their households and, if they choose, their bank accounts so the agency can directly deposit the funds.
Families containing more than 720,000 children who signed up for stimulus checks last year will receive the child tax credit payments, Treasury estimates.
Could $3K child tax credit cause parents to owe IRS more money?
In early August, the IRS is scheduled to allow parents to update their mailing address, and later in the summer, the agency will let families update their income and marital status, as well as the number of dependents, which is important for anyone with babies born in 2021.
This story has been updated with additional data from the Treasury Department.
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