There’s nothing in the program that will tell you this, and it can be a very complicated question. For example, if two spouses earn the same amount of money at work, then one would assume that the taxes owed are also split equally. But if one spouse has very low withholding and the other spouse has a very high withholding, then the refund might belong mostly to the spouse with the higher withholding. Or the tax bill might belong to the spouse who had the lowest withholding.
If you are separating and decide to file jointly, it would be best to agree in advance how to split the refund or tax bill. An accountant could look at your specific situation and give a general estimate or your attorneys may negotiate something as part of your separation or divorce agreement.
