Open a solo 401k plan online in under 10 minutes – The Carry Solo 401k Plan is a featured-packed self-directed account that lets you invest in both traditional and alternative assets, take out a loan, or do a mega backdoor Roth conversion with a few clicks.
Use our solo 401k contribution calculator to determine how much you can contribute into your solo 401k for the 2023 and 2024 tax years. For a quick overview on the different contribution types, limits, and rules for a solo 401k, watch the video below before getting started.
How to use the solo 401k contribution calculator
Step 1: Date of birth
This step is used to determine whether you’re eligible for catch-up contributions. For a solo 401k, you can contribute up to $7,500 more for 2024 if you’ll be at least 50 years of age by December 31, 2024.
Step 2: Business structure
Select whether your business operates as an LLC, s corp, c corp, partnership, or sole proprietorship. All business structures are eligible for a solo 401k, but certain contribution rules can vary depending on your business entity.
Step 3: Tax year
Choose whether you’re calculating contributions for the 2023 or 2024 tax year.
Step 4: Income and expenses
Enter your gross annual income from your business, and your estimated total expenses.
Step 5: Contribution type
Choose whether you’re contributing to your traditional pre-tax account, Roth post-tax account, or both.
Solo 401k contributions explained
Contribution limits
2023
- $66,000 if under 50 years of age
- $73,500 if age 50+
2024
- $69,000 if under 50 years of age
- $76,500 if age 50+
Learn more about solo 401k contribution limits.
Contribution calculations
2023
Out of the 2023 solo 401k contribution limit of $66,000, here’s how the contributions get broken down by employee and employer contributions.
- Employees can contribute up to 100% of their income up to a maximum of $22,500.
- Employers can contribute up to 25% of their compensation if their business is incorporated, and up to approximately 20% if their business is not incorporated.
2024
Out of the 2024 solo 401k contribution limit of $69,000, here’s how the contributions get broken down by employee and employer contributions.
- Employees can contribute up to 100% of their income up to a maximum of $23,000.
- Employers can contribute up to 25% of their compensation if their business is incorporated, and up to approximately 20% if their business is not incorporated.
What income can be contributed?
Compensation is your W-2 income or net adjusted self-employment earnings (outlined below).
For self-employed individuals, compensation is your earned income, which is your net earnings from self-employment after deducting:
- Half of your self-employment tax, and
- Contributions to yourself.
Note: You’ll usually have to pay self-employment taxes if you had net earnings of $400 or more from self-employment. The amount of income subject to self-employment tax is generally 92.35% of your net earnings from self-employment. Learn more here.
As for what type of earned income is allowed to be contributed to a solo 401k plan, read: What Income Is Eligible To Be Contributed To A Solo 401k?
Contribution types
Because you’re the owner of your own business, you can contribute to your solo 401k as both the employee and employer. Employees can contribute as both pre-tax or post-tax, while employers can only contribute as pre-tax.
- Pre-tax: Contributions to your pre-tax solo 401k account are made with pre-tax income and are tax deductible. When you take withdrawals from your pre-tax account in retirement, it gets taxed as regular income.
- Post-tax: Contributions to your post-tax solo 401k account (also known as your Roth solo 401k) are made with post-tax income. You get no tax breaks for your contribution, but withdrawals in retirement are tax-free.
Frequently asked questions
What is the maximum I can contribute to my solo 401k?
- For 2023, you can contribute up to a maximum of $66,000. If you’re at least 50 years of age, you also get catch up contributions in the amount of $7,500 bringing your total contribution limit to $73,500.
- For 2024, you can contribute up to a maximum of $69,000. If you’re at least 50 years of age, you also get catch up contributions in the amount of $7,500 bringing your total contribution limit to $76,500.
How much can I contribute to a Roth solo 401k?
Only employee contributions can be made into the Roth post-tax solo 401k account. Employees can contribute up to $22,500 ($30,000 if age 50+) for 2023 and up to $23,000 ($30,500 if age 50+) for 2024. The calculator will guide you through how to calculate your Roth contribution room.
What is the mega backdoor Roth?
If you wish, you can perform a mega backdoor Roth solo 401k, which allows you to contribute the entire solo 401k limit as Roth post-tax. Essentially, you would be able to contribute up to $66,000 ($30,000 if age 50+) in your Roth solo 401k for 2023, or up to $69,000 ($76,500 if age 50+) for 2024. This option is available with Carry, but not all solo 401k plan providers offer the mega backdoor Roth option.
Are solo 401k contributions tax deductible?
Yes, contributions made to your pre-tax solo 401k account are tax deductible and get deducted from your taxable income for the year. However, withdrawals in retirement get taxed as regular income. On the other hand, contributions made to your post-tax account do not give you any tax deductions, but give you tax-free withdrawals in retirement.
I also have a 401k from my day job. Will my solo 401k contribution limits be affected?
Yes. Employee contributions are aggregated across all of your 401k plans. If you contributed money to your 401k at work, you’ll have to minus that from your employee contribution room for the year. For example, if you’re under 50 years of age, employees can contribute up to $23,000 for 2024. If you contributed $5,000 into your 401k at work, you’ll have $18,000 in room remaining to contribute to your solo 401k as an employee.
How much can I rollover into my solo 401k?
There are no limits on how much you can rollover into your solo 401k from other retirement accounts you own. You can rollover assets from any retirement plan into your solo 401k, except from a Roth IRA.