Read the instructions on the Form W-4. If you follow them carefully, you'll actually come up with 6 withholding allowances. (You don't claim. show more Read the instructions on the Form W-4. If you follow them carefully, you'll actually come up with 6 withholding allowances. (You don't claim dependents on Form W-4, you claim them on your tax return. The relationship is not always linear, either.)
One job only: 1
Head of Household: 1
Child Tax Credit: 2
While I usually suggest that folks cut that by 1 to leave some wiggle room, at your income level that is not necessary. (And claiming 3 as some suggest is too low and very wasteful on your part.)
BTW, the goal is NOT to get "a good amount of money back
at the end of the year" but to come as close to breaking even as possible. That won't be possible in your case since you will pick up a fair payment under the EIC but under any other circumstances you are just lending the government YOUR money all year at zero interest.
Having supported a growing family on a modest income myself, the goal is to get as much money in your hand every payday, not let the government hold it for you. With that in mind, you should consider filing Form W-5 with your employer to have a bit of the EIC advanced to you in your paycheck. You'll still be looking at a "nice" refund next year but this will maximize your money every payday where it will do the most good for you and your child.