You should claim 0 allowances on your IRS W4 tax form if someone else claims you as a dependent on their tax return. (For example – you’re a college student and your parents claim you).
This ensures the maximum amount of taxes are withheld from each paycheck.
You’ll most likely get a refund back at tax time.
This is a good option if you’re single and only have one job.
You may also claim 1 if you’re married but filing jointly—or if you’re filing as the head of household (see def. here).
You’ll most likely get a refund back.
If you’re single and have one job, claiming two allowances is also an option.
You may get closer to your exact tax liability (aka break-even), but you need to be careful because this could still result in some tax due.
If you have more than one job and are single, you can either split your allowances (claim 1 at Job A and 1 at Job B), or you can claim them all at one job (claim 2 at Job A and 0 at Job B).
If you’re married, you can claim two allowances – one for you and one for your spouse. *
If you’re married and have a child, you should claim 3 allowances.
If you’re married with two children, you should claim 3 or more W4 exemptions.