Asking for someone else who needs to be planning for retirement.

$60k job. The company does not offer a 401k match.

So, in this situation... pre-tax dollars into 401k, or post tax dollars into a Roth?

Because of student loan debt that needs attention, maxing out the Roth and then putting into the 401k is not an option.

Thoughts?

Since there is no match I would stop all contributions to your 401k until you are 100% debt free.

Once debt free start at say 15% in a ROTH, then occasionally increase that as time goes on.

I put 25% of my income into my 401k. Small sacrifices now will make for big rewards when you go to retire

What are the time weighted returns for both the 401K and Roth?

Interest rate of student loans? Personally the higher the loan rate the more I would be pushing towards it. Not sure I would stop retirement payments completely unless the rate is above 4%. Max out ROTH IRA space, then put the rest into loans if higher rates.

Came to post this...

If he can't get 15% in ROTH max it and then the rest in 401K or IRA

A Roth IRA is an IRA. Both traditional and Roth IRAs are subject to the combined $5,500 limit with some additional income limits on the Roth. Assuming you're under the income limits (and the OP's subject is at $60k), you can contribute a combined $5,500 spread between the Roth and traditional however you see fit. The combined contributions to both cannot exceed $5,500 in the current tax year.

As for OP's subject, I want more details. What is the interest rate on the student loan? What's the balance left on the student loans? How much money per month does the subject wish to invest/pay to student loans? Are the investment options in the 401K account good?

Since you mentioned the subject has student loans still, I would assume they're relatively young still. At $60k, they're in the 25% tax bracket. The 15% bracket ends at $37,950. If they expect their earnings to increase faster than the rate of inflation/rate the tax brackets are raised, then the Roth could be a good choice.

So you have about $20,000 in income that is taxed at 25%?  Got six months living costs in cash already?  A little security in the bank is good.

Seems like you can save 25% of 20K by putting it in pre-tax IRA, or 20% of 18K max.  I'd go this route and do a roth only if you have the extra money at the end of the year.
I don't know about the back door options.

The interest rate on your debt matters a lot in how fast you pay it down.  What's the annual interest cost compared to the 25% taxes you can save in a retirement investment?

Things might be different next year with Trump's tax plan.

I doubt the person will pinch pennies enough to invest 18K and make student loan payments so socking away what can be done tax free is my best advice.  You get to keep more of your money but you have to wait for it.

Is the Roth the OP is talking about the 401k Roth contribution or self directed Roth? I would do the self directed and stay out of the limited and usually crappy funds in the 401k plans

I would still max out 401k. That's upto 18k tax free money. In reality,  you need to consider everything holistically. Loans, taxes, income, bills etc. Much more to consider.

V

Didn't say how much debt.  He may be able to chew gum and walk at the same time.   Critical to start as early as possible on saving for retirement.  AND,  the pre-tax nature of the 401(k) creates immediate savings that earn compounded interest for years.

My 401k plan has about 30 great funds, avg expense ratio of 45 bps,  S&P index fund at 6 bps.   It's tough to generalize and say "crappy funds".   Many if not most plans today have good fund options.   It's too competitive of a market not to have high performing and competitively priced funds.

It's also good to consider the future directions your career might go.  Planning on starting a business?  You'd want more post tax investments so you have more to
start it.

I stuck with pre tax retirement investing and Roth next and don't have much cash now at 51yo.  A few toys and a paid off house is what I have for post tax assets after 25 years of lower middle class hourly wages.  Retirement assets are fairly solid though.

When consider pre-tax vs post-tax retirements there are a number of factors that you must consider and what is right for one person may not be right from you. Therefore it is wise to completely ignore anybody that says "do this, it's the best". Just because it's best for them, or just because their advisor, or best friend etc said it was best for them, doesn't mean it's best for you.

That being said, some of the factors that you must consider are, expected taxation now vs. then. Not just tax-rate, but expected tax bracket (which will depend on what your distributions will look like during retirement). Things that some don't consider but really should are the benefits of reducing your MAGI now. IE, is there is a tax credit or other financial benefit that you would qualify for if your MAGI was decreased but you wouldn't qualify for if your MAGI isn't decreased? If so, you want pre-tax contributions so you can reduce your MAGI and qualify for that benefit. For example, my wife and I sometimes exceed the cutoff for the Child Tax Credit, in the years we have extra income (overtime, extra farm income etc) I increase my 401k contributions to adjust our MAGI down.

All other factors held the same, equal tax rate now & retirement, pre-tax vs. post-tax work out exactly the same. Some people will tell you that, "all your gains grow tax-free in a Roth", but the thing they forget to account for is that the balance starts lower because of the tax so it has to catch up to the balance of the pre-tax; it will never catch up UNTIL the pre-taxed gets taxed in retirement.

A traditional 401k and Roth IRA have polar opposite tax treatments.  I think it's extremely challenging for anyone to definitively say that one strategy is going to win over another 30 years from now when you are getting ready to retire.  

Therefore, the optimal strategy, in the absence of a company match, would be to split your contributions evenly between both.

Both. Your 401k will help you today by lowering your taxable income this year, and in the future, no tax money will be due on Roth IRA money withdrawn at retirement.