The number of dependents you claim are needed to factor the type of child tax credit you’ll get on your tax return. They are either under 17 (16 and younger) or over 16 (17 and older).
If your income is below $400,00 for Married Filing Joint, or $200,000 for the other filing status, then the child tax credit for those under 17 (16 and younger) is $2,000 per child. For those over 16 (17 and older) you get the ‘other dependent’ credit of $500 per dependent. This information is entered on the W4, line 3 https://www.irs.gov/pub/irs-pdf/fw4.pdf and will lower the amount withheld from your paycheck.
You will want to get an estimated projection to see how your current information will result at the end of the year. You can use the TurboTax W4 Calculator to assist: https://turbotax.intuit.com/tax-tools/calculators/w4/
These results can assist in determining whether you should add or remove dependents.
Hello, please see below link to assist you on filing for federal withholding