<prompt> Human: I was paid a large paycheck this week, due to owed back pay, totaling about 11,500. Of that, 5,400 went to federal withholding, social security, Medicare, and California withholding. This seems insane. With this backpay, my yearly earnings are at 41,000, and of that, 20,000 has gone to income taxes. My W4 is set to single, 0 allowances. Can someone more knowledgable about taxes please help me understand why Im getting taxed so heavily?  <response>: First, you are being withheld heavily, not necessarily taxed heavily. Those are two different things. However, if you are single, and do not itemize deductions, it appears you will be in the marginal 25 federal tax bracket. In addition, Medicare and Social Security taxes are a flat 7.65. Your California marginal tax bracket appears to be 9.3, meaning that your total marginal tax on the income appears to be around 42.So, the withholding is probably a little rich, but you will have the excess refunded to you when you file your taxes next April. My guess is that overall, you are probably having a bit two much withheld, meaning you will get a decent refund when you file. 