If you have a Solo 401k, or want to establish a plan for the 2023 tax year, here are all the important dates and deadlines you’ll need to know for setting up a plan, making contributions, and filing forms to the IRS.
Before you dive in, download a printable PDF guide with all the important dates you need to know for the 2023 tax year.
Free PDF
Solo 401k Important Deadlines
Download a PDF with all the important dates and deadlines you need to know for Solo 401k Plans.
| What’s Due? | Description | Deadline |
|---|---|---|
| Deadline to open a Solo 401k plan | If you don’t have a Solo 401k plan but want to set one up for the 2023 tax year, it must be established by December 31, 2023. | December 31, 2023 |
| Deadline to make an election for employee contributions | If you want to make employee contributions for the 2023 tax year, you must make an election by December 31, 2023. | December 31, 2023 |
| Deadline to file Form 945 | If you took an early distribution from your Solo 401k in 2023, you must report the amount withheld on Form 945. | January 31, 2024 February 10, 2024 if you’ve already paid your taxes for 2023 in full. |
| Deadline to Form 1099-R | If you moved any money out of a Solo 401k plan in 2023, you’re required to report it to the IRS by filing Form 1099-R. | February 28, 2024 if paper filing. March 1, 2024 if e-filing. |
| Contribution deadline | If your business structure is an S corporation, partnership, or LLC taxed as an S corporation or partnership, this is the deadline to make employer and employee contributions. | March 15, 2024 |
| Contribution deadline | If your business structure is an C corporation, sole proprietorship, or LLC taxed as a sole proprietorship, this is the deadline to make employer and employee contributions. | April 15, 2024 |
| Deadline to file Form 8606 | If you contributed money into a non-deductible IRA (usually for the purposes of a mega backdoor Roth conversion), you’ll have to file Form 8606. | April 15, 2024 |
| Deadline to file Form 5500-EZ | This form is required if you’re closing your Solo 401k plan or if you have $250,000 or more in assets in your account. | 7 months after your fiscal year end. If following the calendar year, it is due July 31, 2024 |
| Extended contribution deadline | If you requested a tax extension, you’re given an additional 6 months to make your contribution into your Solo 401k plan. | September 16, 2024 for S corporations, partnerships, and LLCs taxed as S corporations or partnerships. October 15, 2024 for C corporations, sole proprietorships, and LLCs taxed as sole proprietorships. |
📌 December 31, 2023
Deadline to set Up a Solo 401k plan
(If you do not already have a Solo 401k Plan established)
If you don’t have a Solo 401k plan yet, and want to make contributions for the 2023 tax year, you need to establish a plan by December 31, 2023. (It takes 10 minutes to set up your plan with Carry – Click here to get started).
Deadline to make an Election
(If you wish to make employee contributions for the 2023 tax year)
In order to make employee (salary deferral) contributions to your Solo 401k, you need to make an election by December 31, 2023. A Solo 401k election is simply a written form or document for how much in employee contributions you want to make, and to which accounts it should go towards (pre-tax or Roth). Since you are the employer and employee, you’re essentially writing a signed, dated note to yourself on the amounts you are going to contribute as an employee, and keeping it on file yourself for your own records, in case the IRS ever asks for it. No money needs to be contributed into your plan at this time.
Exception for sole proprietorships
If you operate your business as a sole proprietorship, the SECURE 2.0 Act gives you more time to set up your Solo 401k plan and make your first elective deferrals. Instead of having to open a plan and make an election by December 31, 2023, you can establish and contribute to the plan until the federal tax filing deadline (April 15, 2024). However, extensions would not be allowed.
📌 January 31, 2024
Deadline to file Form 945
(If you took an early distribution from your Solo 401k in 2023)
You must file Form 945 if you took an early distribution from your Solo 401k plan in 2023. When you take an early distribution from your Solo 401k, you’re required to pay a 10% penalty plus income taxes on the amount withdrawn. Because of this, you’re required to withhold 20% of the distribution for federal income taxes. Form 945 would need to be used to report the amount withheld. If your tax liabilities for the 2023 year were already paid in full, you may file Form 945 by February 10, 2024.
📌 February 28, 2024
Deadline to file Form 1099-R through paper filing
(If you moved money out of your Solo 401k in 2023)
If you moved any money out of a Solo 401k plan in 2023, you’re required to file Form 1099-R. The deadline is February 28, 2024 if you choose to file through paper filing. Moving money applies to all withdrawals, rollovers, Roth conversions, mega backdoor Roth conversions, RMDs, and failed Solo 401k loan payments.
📌 March 1, 2024
Deadline to file Form 1099-R through E-filing
(If you moved money out of your Solo 401k in 2023)
If you moved any money out of a Solo 401k plan in 2023, you’re required to file Form 1099-R. The deadline is March 1, 2024 if you choose to file through E-filing. Moving money applies to all withdrawals, rollovers, Roth conversions, mega backdoor Roth conversions, RMDs, and failed Solo 401k loan payments.
📌 March 15, 2024
Deadline to make employer & employee contributions
(For S corporations, partnerships, and LLCs taxed as S corporations or partnerships)
S corporations, multi-member LLCs and partnerships must make employer contributions by this date. If you made an election to make employee contributions, the money needs to be contributed by this deadline. If an extension is filed, the deadline is extended to September 16, 2024.
📌 April 15, 2024
Deadline to make employer & employee contributions
(For C corporations, sole proprietorships, and LLCs taxed as sole proprietorships)
C corporations, sole proprietorships, and LLCs taxed as sole proprietorships to make employer contributions. If you made an election to make employee contributions, the money needs to be contributed by this deadline. If an extension is filed, the deadline is extended to October 15, 2024.
Deadline to file Form 8606
(If you contributed money into a non-deductible IRA in 2023)
If you contributed money into a non-deductible IRA in 2023, you’ll need to file Form 8606 to the IRS. A non-deductible IRA is often used to perform mega backdoor Roth conversions into a Roth Solo 401k. You can file Form 8606 with your annual tax return by the federal tax filing deadline, which is usually April 15th of each year.
📌 July 31, 2024
Deadline to file Form 5500-EZ
(If you’re closing your Solo 401k Plan or if your account asset value is $250,000 or greater)
The deadline to file IRS Form 5500-EZ is 7 months after your fiscal year end. If your business uses the calendar year, it is due by July 31, 2024. You only need to file Form 5500-EZ if you wish to close your Solo 401k plan, or if your account asset value is $250,000 or greater as of December 31, 2023. However, at Carry, we recommend filing one every year as there are some edge cases where it can act as a safeguard. It only takes a few minutes to file and we help all of our clients file the form to the IRS.
📌 September 16, 2024
Extended contribution deadline
(For S corporations, partnerships, and LLCs taxed as S corporations or partnerships)
S corporations, partnerships, and LLCs taxed as S corporations or partnerships have until September 16, 2024 to make their employer and employee contributions if an extension was filed by March 15, 2024.
📌 October 15, 2024
Extended contribution deadline
(For C corporations, sole proprietorships, and LLCs taxed as sole proprietorships)
C corporations, sole proprietorships, and LLCs taxed as sole proprietorships have until October 15, 2024 to make their employer and employee contributions if an extension was filed by March 15, 2024.
Frequently asked questions
When is the deadline to set up a Solo 401k?
If you wish to set up a Solo 401k plan for the 2023 tax year, you must establish a plan by the last day of the year (December 31, 2023). Due to the tight deadline, and the end of December being the holidays, it’s recommended to try and set up the plan a few days prior to December 31.
If you operate as a sole proprietorship, you have until April 15, 2024 to open a plan and make your contributions for the 2023 tax year. However, no extensions would be allowed in this case.
Set up a plan with Carry in under 10 minutes, or compare the best Solo 401k plan providers here.
When is the last I can make my contribution into my Solo 401k?
- For S corporations, partnerships, and LLCs taxed as S corporations or partnerships, the contribution deadline is March 15, 2024. With an extension, the due date is extended to September 16, 2024.
- For C corporations, sole proprietorships, and LLCs taxed as sole proprietorships, the contribution deadline is April 15, 2024. With an extension, the due date is extended to October 15, 2024.
How much can I contribute to my Solo 401k?
For the 2023 tax year, you can contribute a total of $66,000 into your Solo 401k. If your age is 50 or above by December 31, 2023 you’re allowed an additional $7,500 in catch-up contributions, bringing your total to $73,500.
What’s the difference between employee and employer contributions?
With a Solo 401k plan, you have full control over both your employee and employer contribution amounts. Employee and employer contributions are subject to different limits, and are treated differently in certain circumstances.
- Employee contributions are technically “employee elective salary deferrals,” meaning they represent a portion of your pay going into your Solo 401k, instead of your personal bank account (even if, as a self-employed individual, you don’t have a regular salary). As an employee, you can contribute up to 100% of your compensation, up to a maximum of $22,500 ($30,000 if age 50+). Employee contributions can be made as pre-tax or Roth.
- Employer contributions are technically “employer profit-sharing contributions,” and represent an amount separate from your “salary” that is paid directly into your plan. As an employer, you can contribute up to 25% of your compensation if your business is incorporated, and approximately 20% if your business is not incorporated. Employer contributions can only be made as pre-tax.
The total contributions on both sides must not be exceed the total 2023 Solo 401k contribution limit, which is $66,000 ($73,500 if age 50+).
Also read: Solo 401k Contribution Types Explained
Is there a deadline to rollover funds from another retirement account into a Solo 401k?
No, there is no deadline to transfer assets into your Solo 401k from another retirement plan, and there’s also no limit on how much you can rollover. Furthermore, rollovers do not affect your contribution limits for the year.
Do I need to be aware of any tax forms?
Yes, here are the important forms you need to be aware of if you have a Solo 401k:
- Form 5500-EZ: Required only if you’re closing your Solo 401k plan, or if you have $250,000 or more in plan assets. However, at Carry, we recommend all of our users to file one every year, regardless of their plan assets.
- Form 1099-R: Required any time funds/assets are moved out of your solo 401k account whether it’s a distribution, rollover, in-plan conversion, or RMD.
- Form 945: Required when you take an early distribution from your solo 401k plan in order to report the 20% withheld amount from your withdrawal.
- Form 8606: Required when you use a non-deductible IRA in order to rollover to a Roth solo 401k.
For more details, also read: Important Forms for Solo 401k Owners
