Solo 401k Roth Earned income minimums?

[BajaRed]

Looking for ways to put more into Roth and retirement vehicles.  I am self employed, and live abroad and have max 15% tax rate(SE tax after foreign earned income exclusion). 

My tax returns show about 20k earned income, and I have consistently taken advantage of Roth IRA with the annual limit of about 6.  I now see solo 401k Roth, which has about 19k limit. 

Could I open solo 401k roth and contribute say 14k and 6k to roth IRA?  Such that the contributions are almost the same (20k), or possibly more than my earned income? 

Essentially I would be moving some of my stache from taxable account into 401k Roth. 

[BajaRed]

I see that 18k is the annual limit for salary deferral across retirement vehicles, but as plan owner it seems I could exceed that profit sharing contributions, to myself.

[terran]

$18k salary deferral is across all employer plans (401k, 403b). It doesn't include IRAs. You can also contribute profit sharing contributions to a solo 401k. Remember that you have to account for the employer half of self employment tax and some other calculations when figuring the maximum amount you can contribute to a solo 401k. See the worksheet at: https://www.irs.gov/publications/p560#en_US_2016_publink10009065 -- the spreadsheet I made based on that worksheet says for a total self employment net income of $20k, you could contribute $18,294 to a solo 401k.

You can only contribute to an IRA to the extent that you have earned income in excess of the contribution. I'm not sure what the interplay would be between earned income and solo 401k contributions in this case since most of your income would be going into the 401k. You might be able to "double dip" but you'd need to look into that more.

[BajaRed]

Thanks for that clarification!