I have a full time job and I have a side business. I established a self-employed 401(k) plan, also known as a solo 401k plan or an individual 401k plan, for my side business. This allows me to shelter a little bit more money for retirement from my self-employment income. Every bit helps, you know?
When I tried to figure out how much I can contribute from my self-employment income to the solo 401k, I found that the information on the Internet assumes that the self-employment income is the person’s only earned income. For example the calculation worksheets provided by Fidelity, Schwab, and Vanguard all make that assumption. They don’t consider the cases like me who work at a day job while earning some self-employment income on the side.
Because I participate in the 401k plan at work, the maximum I can contribute to my solo 401k plan changes with what I earn from my day job and what I contribute to the workplace 401k plan. The Social Security tax I pay depends on the sum of my salary as an employee and my self-employment income. The salary deferral contributions I can make from self-employment income also depends on how much I already contribute to my 401k plan at my day job.
I would think there are enough consultants, freelancers, moonlighters, and bloggers who are in the same camp as I am, but there is very little resource I could find for people who earn their income from a mix of W-2 salary and self-employment.
You know where this is going to lead to, don’t you? I had to create a spreadsheet for myself and I’m sharing it here in case other people like me find it helpful.
Spreadsheet: Solo 401k For Part-Time Self-Employment
This spreadsheet takes into account employment income, contributions to workplace 401k, and self-employment income. It calculates the maximum salary deferral contribution and the maximum profit sharing contribution I can make to my solo 401k plan.
If there is no day job, just set the day job related fields to zero and it will work for people who only have self-employment income as well. There are two tabs: one for an unincorporated business (sole proprietorship), the other for an incorporated business. As usual, use this and everything you find on this blog at your own risk, because I’m not a CPA.
I’m going to use Fidelity for my plan because I already have other accounts with them and their plan is free and flexible. Vanguard is going to offer a plan but it looks like they don’t allow incoming rollovers and there is no brokerage option.
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