Before Tax versus Atfer Tax 401K contributions?

If they offer a Roth option and you are more than 10 years from retirement, go with the after tax Roth. You'll make out much better in the long run as all distributions will be entirely tax free.

If they don't offer a Roth option, making after tax contributions makes for major bookkeeping headaches when you start taking distributions since you must determine the taxable and non-taxable portions each year. While your original contributions are not taxable, the gains are taxable.

For most folks the present year tax reduction is worth more than the modest tax savings down the road from making after tax contributions to a traditional 401(k). I have a couple of old plans from past years where the gains in the plan are more than 10 times my original contributions. Saving 15% in tax on 7% of the distributions just won't add up to much especially when I saved 28% in taxes on the funds going in.

Do it before taxes. It lowers your taxable income (for income taxes - Social Security and Medicare taxes still apply), and could lower it to a lower tax bracket. End result is more money you get.

And depending on what age you are, 5% may be good. But as you get raises through your career, also give your 401(k) a little raise also by bumping up your contribution a little. And this is more true the older you get and closer you get to retirement.

Before taxes lowers your income and thus your tax burden.

a 401k plan is automatically PRE-TAX

this is a good plan, stay with it