<prompt> Human: Just confused and trying to better understand. Spouse and I both claim married 0. We file jointly, no children and both make pretty decent salaries and own a home. This year we owe and I dont understand why. Anyone care to help me understand?  <response>: You dont provide the amount you earn or the amount you had withheld throughout the year. Both of those are necessary to being able to answer your question fully.However, you say both you and your spouse work and claim 0. The W-4 assumes that when you select married youre the only spouse whos working. It does not account for your spouse also working. You need to use the Two EarnersMultiple Jobs worksheet included with the W-4 to accurately determine what to put on your W-4s. Its likely that due to how you filled out your W-4s, you underwithheld throughout the year, so now you owe. 