Is it true that ultimately a couple has to pay more tax if both of them earn in comparison to one of them earning? My friend Emily's husband used to work and they filed tax jointly but now Emily has got a job but the salary is not much. Her friend has suggested to check out whether or not they'll have to pay much more since they file jointly. Since she won't be earning much, so if they calculate, they'll have to pay more tax than what she'll earn in a year.