Will I get penalized if I claim a dependent on the Massachusetts M-4 form

Here is the form and instructions.

https://www.mass.gov/doc/form-m-4-massachusetts-employees-withholding-exemption-certificate/download

Suppose you expect to qualify as HOH with 1 dependent on your tax return.  The withholding system is supposed to allow you to break even (or come close) if you claim HOH and 1 dependent.  If you don't add the dependent, or you don't check the HOH box, you will have more money taken out of each paycheck.  That would mean less money to spend each week, and a bigger refund at the end of the year.  If you do add the dependent and check the HOH box, your withholding should be about the same as your tax, meaning you get more money in each paycheck but get a small or no refund at the end of the year.  

The most common situation where this does not work right is if you have more than one job at the same time. If that is the case, we will have to look for more detailed instructions for that situation, because claiming a dependent and HOH on both your jobs will result in have too little tax withheld and owing tax at the end of the year.  But if you only have one job at a time, the system should balance for you.