What they take out in taxes doesn't matter. What matters in the end is your total tax liability. (What you SHOULD have paid the government in taxes).

If you paid them $12k throughout the year, and should have paid them $10k, you will get $2k back. Conversely, if you paid them $8k and owed $10k, you would have to pay them money at the end of the year.

Now, if you are getting a lot of bonuses (which most companies tax at 25% - yours may tax it differently, but 25% is accounting industry standard), and you actually pay less than 25%, then you will likely get money back from what you paid extra. If your tax liability is 20%, and you pay 25% in bonus taxes, then you will obviously get that 5% back.

Now, what tennis was saying...

If you are getting a lot of bonuses which are taxed at a higher rate than you normally pay, you can increase the number of dependents (for example) to more than you really have. You would have to pay less in tax each month, but your bonus will still be taxed the same way.

So, you would be shorting the government in your regular paycheck taxes. BUT... you would be overpaying with what is taken out for bonuses. If your accountant is good, you can make it so these two numbers are almost equal. At the end of the year, you will pay exactly in taxes what your total tax liability is.

In the end, all the government cares about is that you paid them what they are owed. (Businesses are different, and required quarterly or monthly tax estimates MUST be made).

Personally, this is too much work for me. I have 3 kids, claim three, and get $3800 back in taxes. But if you are smart, you can do it.