Lower total tax if one of you has a smaller income
Tax brackets are set on income levels and determine the rate at which an individual is taxed. The more money you make, the more taxes you'll pay. The less money you make, the less taxes you'll pay. Pretty easy, right?
If one of you makes a much lower salary than the other, your tax bracket will go down to meet somewhere in the middle. As a result, you'll pay a much lower tax payment than if you had
The Unlimited Marital Deduction allows an individual to give any amount of money as a gift to their spouse, even after death, free from tax . The only catch is that the spouse receiving the gift must be a U.S. citizen. Different rules apply for spouses who do not have citizenship.
You can benefit shop
If both of you receive benefits from your job, take time to examine who has the better benefits in each category. You can then pick and choose the best benefit plan to fit your needs. For example, according to TurboTax, if one spouse can have pre-tax money deposited in an IRA fund and the other spouse can't, they can put family money into an IRA for the second spouse, too . Having the right mixture of benefits can be beneficial in the long run.
Last but not least, filing one tax return is easier
This one may be a little more obvious, but it's always easier to file jointly than it is to file separately. In some cases, filing one tax return can also cost less depending on your amount of paperwork and the extent of the return.
 Unlimited Marital Deduction, Investopedia
 Seven Tax Advantages of Getting Married, TurboTax