Sounds like you are living in the days of personal exemptions---which ended after 2017 when the tax laws changed. There are no personal exemptions that make each dependent "worth" a certain amount to you.
For children under the age of 16 you can now get the child tax credit or for dependents over 16 you can get the $500 credit for other dependents.
The new W-4 form is different---read instructions carefully.
https://turbotax.intuit.com/tax-tools/calculators/w4/
https://www.irs.gov/individuals/tax-withholding-estimator
https://www.irs.gov/pub/irs-pdf/fw4.pdf
https://ttlc.intuit.com/questions/1900923-what-is-the-child-tax-credit
https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/additional-child-tax-credit/L6x...
https://www.irs.gov/help/ita/does-my-childdependent-qualify-for-the-child-tax-credit-or-the-credit-f...
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
