<prompt> Human: Between my wife and I, we are expecting to earn about 130,000 annually gross Expecting about 25,000year in itemized tax deductions for the foreseeable future kids, house, charitable giving. 184,000 in traditional 401k and 403bs from past jobs 10,000 in one Roth IRA, contribute the max every year Wife has a traditional 401k for her current job Both Wifes job and mine have employer contribution matching We are both 38 years old and plan on retiring around 65Like the title says, I have a new job and have the option of contributing to a Roth 401k or traditional. Which ones does it make sense to choose?  <response>: So, Im not sure what your level of knowledge is on the topic, so Ill give a very thorough answer, then a tl;dr version at the end.Is the 130K before or after your wifes current 401k contributions? How much do each you and she plan to contribute to the 401k?Assuming you are MFJ, your taxable income is 130K - 25K, or 105K-ish. That may be reduced further by certain non-retirement, non-1040 tax deductions that are realized by a reduction in W-2 income eg - health insurance premiums for an employer-sponsored plan. Since you used the term gross, Im going to assume you didnt already subtract out this type of deduction.So lets say 100K-ish. The new 12 bracket caps out at 77,400 for MFJ.Each you and your wife can contribute up to 18,500year to a 401k. Moreover, if your employer offers both traditional and Roth 401ks, youre typically able to sign up for and contribute to both, as long as total contributions are less than 18,500year.My suggestion would be this. Calculate out your actual bottom-line taxable income for 2018, assuming neither you nor your wife contribute a cent to any type of retirement account. For now, well use the 100K rough estimate, but youll want to figure out the real figure and re-do the calculations with that.Subtract 77,400 from the number you calculated. So, if we went with 100K, that figure would be 22,600.Now figure out you and your wifes expected 401k contributions. If its less than 22,600 combined, use traditional 401ks. If its more than 22,600 combined, use traditional 401ks for the first 22,600 and Roth 401ks for all dollars contributed in excess of 22,600.Basically, if you can get down into the 12 bracket, your Roth contributions start to only cost you 12 in taxes. You already have a couple hundred thousand dollars in pre-tax retirement savings in your 401ks. All future employer match contributions and most of your future contributions will continue to be pre-tax as well even if your contributions are partially Roth. And all this pre-tax money has an additional 27 more years to compound. Also, its unlikely that the current historically-low tax brackets are going to be sustainable for the next 25 years. When you add all these facts together, Id say its highly unlikely that your post-retirement tax bracket will be lower than 12. If this prediction bears out, my strategy doesnt cost you anything, and may actually save you money.Furthermore, having significant pots of Roth and non-Roth money can help you better pick your bracket in retirement. In essence, take an annual dispersement from the non-Roth accounts that puts you at the very top end of your desired tax bracket. Then, pull any additional money you may need for the year from the Roth accounts.Tl;dr answer: Why not both? Work with a tax professional to estimate your taxable income minus all non-retirement deductions; contribute enough to the traditional 401k to get you down into the 12 bracket. Then contribute any additional dollars to a Roth 401k. 