Originally Posted by Al18
Also, the amount you invest in a 401K and IRA can't be more than your part-time work earnings.
401k can't exceed your individual gross income but as far as I'm aware, IRA is limited based on combined spousal income if married filing jointly. Even if only one spouse worked and earned, say $50K, both spouses can contribute $5500 each ($6500 if age 50 or older) to an IRA so total of $11-13K. I prefer the Roth IRA route over Roth 401k if possible as it offers a greater degree of flexibility.
Not sure how much you're earning part time but standard deduction + exemption for MFJ is $20K (0% tax). Next $18K ($38K gross) is just at 10% and the next $56K ($95K gross) at 15%. I'd probably just contribute enough to tax deferred accounts until regular income (wages, interest, etc) + LTCG/qualified dividends reaches one of those notch points and put the rest in Roth (IRA first then 401k).