Your elective deferrals are limited by person, not plan. So, the maximum elective contributions to the 403b plan would include both your W2 job deferrals and any deferrals you make if you create a solo 401k for your side job. The benefit you could get in addition with a solo 401k would be the employer nonelective deferrals.
Per the IRS:
The owner can contribute:
Employer nonelective contributions up to:
- 25% of compensation as defined by the plan, or
- Contribution limits for self-employed individuals:
- You must make a special computation to figure the maximum amount of elective deferrals and nonelective contributions you can make for yourself. When figuring the contribution, compensation is your “earned income,” which is defined as net earnings from self-employment after deducting both:
- one-half of your self-employment tax, and
- contributions for yourself.
See also Calculating Your Own Retirement Plan Contribution.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
