Hello. I'm hoping someone may be able to guide me to the correct answer.
I contribute to a University sponsored 401(a). These are mandatory contributions in the amount of 7.5% of my gross with 6% employer contribution.

I also participate in an optional 403(b) plan via the University.

Now, I've opened up a self-employed 401(k) for my consulting business.

I've received conflicting responses on the max I can contribute to the SE 401(K).

Answer 1: 14,000 - my 403b contribution - my 401a contribution

Answer 2: 14,000 - my 403b contribtion

Can anyone help clarify this matter or point me to the relevant sections of the IRS code?

Thanks

See Internal Revenue Code Section 402(g), particularly 402(g)(3).

But, for your self-employment income, you might consider a regular plan formula, rather than a 401(k) type formula. The 402(g) cite is to your elective deferrals to a 403(b) or 401(k) plan. If you are the employer and the sole worker for your consulting business, you can make a contribution of basically 20% of your net earnings from self-employment (THAT IS A GROSS SIMPLIFICATION AND YOU NEED TO GET TAX ADVICE.) This is a lower limit, but not included in the $14,000 cap of Section 402(g). There may be other complexities with your 403(b) plan depending on the amount of wages you get from the University.

No one faces a more complex retirement plan contribution deduction calculation than a University employee with an outside source of self-employment income.