2024 & 2025 SOLO 401k LIMITS & DEADLINES
✅ 2024 Employer + Employee Contribution Limit: $69,000 ($76,500 if age 50 or older).
✅ 2025 Employer + Employee Contribution Limit: $70,000 ($77,500 if age 50 or older).
✅ Employee Contributions: Up to $23,000 in 2024 or $23,500 in 2025. If you’re 50 years of age or older, the limits increase to $30,500 in 2024 or $31,000 in 2025. Contributions can go into a traditional or Roth Solo 401k.
✅ Employer Contributions: Generally up to 25% of compensation (or around 20% if you’re not incorporated). These contributions typically go into a traditional (pre-tax) Solo 401k, as Roth options may not be available with all plans.
✅ Total Contributions: Cannot exceed the annual limit.
✅ Plan Setup & Election Deadline: Must set up your plan and elect employee contributions by December 31 of the contribution year.
✅ Contribution Deadline:
- 2024 contributions: Due by March 15, 2025 (S corps, multi-member LLCs, partnerships) or April 15, 2025 (C corps, sole proprietors, single-member LLCs).
- 2025 contributions: Due by March 15, 2026 or April 15, 2026, depending on business type.
- Extensions available for an additional 6 months.
Looking to open a Solo 401k plan? Get started today with just a few clicks – 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.
A Solo 401k allows eligible individuals to contribute as both the employer and the employee, with different limits and deadlines for each. These rules can also vary depending on your business structure.
If you’re considering opening an account to make last-minute 2024 contributions, you may still have time before the tax deadline. If you’re planning ahead for 2025, here’s a general breakdown of the contribution limits and the important deadlines to remember.
2025 Solo 401k Contribution Limits
Here’s a quick breakdown of the 2025 Solo 401k contribution limits, including employee and employer contributions, catch-up contributions, and total limits.
| Contribution Type | Contribution Amount |
|---|---|
| Employee | $23,500 ($31,000 if for ages 50 or older) |
| Employer | 25% of W-2 earnings or net adjusted self-employment earnings (~20% if you’re not incorporated) |
| TOTAL | $70,000 ($77,500 if for ages 50 or older) |
The total combined Solo 401k contribution limit for 2025 is $70,000, generally split between employee and employer contributions, each with their own set of rules. If you’re at least 50 years old by December 31, 2025, you may qualify for an additional $7,500 in catch-up contributions. This increases your total limit to $77,500.
While the table above outlines the limits, your actual contribution amounts depend on your income, age, and business structure.
Employee contributions may go into a pre-tax or Roth Solo 401k, depending on your provider. Employer contribution limits are based on a percentage of income — typically up to 25% of W-2 wages or around 20% of net earnings if unincorporated.
📌 Also read: Solo 401k Contribution Types Explained
How Much Can I Contribute to a Roth Solo 401k in 2025?
The Roth Solo 401k contribution limit for 2025 is $23,500 (or $31,000 if you’re age 50 or older).
Previously, only employee contributions to a Solo 401k could be designated as Roth. However, starting in 2023, the SECURE 2.0 Act allows employer contributions to be Roth as well. As a result, the total Roth Solo 401k contribution may now potentially include both employee and employer contributions — depending on your plan provider and how the plan is set up.If your plan permits after-tax contributions, you may be able to exceed standard Roth limits by using a Mega Backdoor Roth Solo 401k conversion. Note that this strategy requires proper execution to avoid tax issues.
2024 Solo 401k Contribution Limits
Below is an overview of the 2024 Solo 401k contribution limits, including catch-up amounts and how much you might be able to contribute.
| Contribution Type | Contribution Amount |
|---|---|
| Employee | $23,000 ($30,500 if for ages 50 or older) |
| Employer | 25% of W-2 earnings or net adjusted self-employment earnings (~20% if you’re not incorporated) |
| TOTAL | $69,000 ($76,500 if for ages 50 or older) |
The total combined Solo 401k contribution limit for 2024 is $69,000, split between employee and employer contributions, each with its own rules.
If you’re age 50 or older by December 31, 2024, you may be eligible for an additional $7,500 in catch-up contributions, bringing the total limit to $76,500.
Specific contribution limits depend on income and business type. Employee contributions may go into a pre-tax or Roth Solo 401k, depending on your provider. Employer contributions are generally up to 25% of net adjusted income, or about 20% for unincorporated businesses.
How Much Can I Contribute to My Roth Solo 401k in 2024?
In 2024, the Roth contribution limit follows the standard employee deferral limits — $23,000, or $30,500 with catch-up contributions if you’re age 50 or older.
Since Roth contributions come from employee deferrals, the Roth Solo 401k limit follows the same rules.
Solo 401k Contribution Deadlines for 2025
Contribution deadlines vary depending on several factors, so it’s important to understand which dates apply to your situation. The deadlines for employee and employer contributions are different and may also vary based on your business entity type.
The table below provides a general overview of key deadlines for making Solo 401k contributions in 2025.
| Contribution Type | Action | Deadline | Notes |
|---|---|---|---|
| Employee | File Solo 401k & deferral election | December 31, 2025 | Determines your contribution amount and whether it’s Roth or pre-tax |
| Employee | Fund Solo 401k contributions | April 15, 2026 | Federal tax deadline |
| Employer | Fund Solo 401k contributions (sole proprietorship, C corp, or LLC taxed as sole proprietorship) | April 15, 2026 | Standard federal tax deadline |
| Employer | Fund Solo 401k contributions (S corporation, partnership, or LLC taxed as corporation) | March 15, 2026 | One month earlier than the standard deadline |
Deadlines for Employee Contributions
Employee contributions have two key deadlines: one for setting up the plan and filing your deferral election, and another for depositing the contribution.
✅ Election deadline – December 31, 2025
If you don’t yet have a Solo 401k, you’ll need to set up your account and file a deferral election by December 31, 2025 in order to contribute for the 2025 tax year.
Missing this deadline may disqualify you from making employee contributions for that year.
However, you don’t need to deposit the funds yet — only to file your deferral election, which informs the IRS of how much you intend to contribute and whether the amount will go into a pre-tax (traditional) or after-tax (Roth) Solo 401k.
📌 Learn more about Solo 401k elections here.
✅ Funding deadline – April 15, 2026
After filing your deferral election, you generally have until the federal tax deadline, April 15, 2026, to fund your Solo 401k account with your employee contributions.
Deadlines for Employer Contributions
For employers, the contribution deadline depends on how your business is structured.
✅ Funding Deadline – April 15, 2026 (Most Businesses)
If you operate as a sole proprietorship, C corporation, or an LLC taxed as a sole proprietorship, you’ll generally need to fund employer contributions by April 15, 2026.
✅ Funding Deadline – March 15, 2026 (S Corps & Partnerships)
If your business is structured as an S corporation, partnership, or an LLC taxed as a corporation, your contribution deadline is typically March 15, 2026.
✅ Extended Deadlines (If Filing for a Tax Extension)
If you file for a tax extension and it’s approved, you may receive an additional six months to make your contributions.
- If extended, a sole proprietorship, C corporation, or LLC taxed as a sole proprietorship will generally have until October 15, 2026 to make employer contributions.
- A partnership, S corporation, or LLC taxed as a corporation will generally have until September 15, 2026.
If you’re not sure when to file, speak with your tax professional to make sure you don’t miss your deadline.
2024 vs 2025 Contribution Limits – What’s Changed?
The table below provides a side-by-side overview of the main Solo 401k contribution limits for 2024 and 2025:
| Contribution Type | 2025 Contribution Limits | 2024 Contribution Limits |
|---|---|---|
| Employee Elective Deferrals | $23,500 ($31,000 if age 50 or older) | $23,000 ($30,500 if age 50 or older) |
| Employee catch-up contributions | $7,500 | $7,500 |
| Employer contributions | 25% of compensation (20% if you’re not incorporated) | 25% of compensation (20% if you’re not incorporated) |
| Total Contribution | $70,000 ($77,500 if at least 50 years old) | $69,000 ($76,500 if 50 years old and above) |
When comparing the two years, 2025 includes slightly higher contribution limits than 2024. This may allow for additional contributions, depending on your income and plan eligibility.
In 2025, eligible employees may contribute an additional $500 in elective deferrals, increasing the limit from $23,000 to $23,500 — or from $30,500 to $31,000 for those age 50 or older.
The catch-up contribution remains unchanged at $7,500. This results in a total contribution limit of $77,500 in 2025, compared to $76,500 in 2024 for those who qualify.
Additionally, the remaining room for employer contributions increases from $46,000 in 2024 to $46,500 in 2025, assuming the employee contribution limit is fully utilized. This extra $500 might seem small, but it may have a compounding effect over time — though investment performance isn’t guaranteed and results will vary.
Solo 401k Contribution Limits for Prior Years
According to historical IRS limits, Solo 401k contribution limits have generally increased by around $1,000 per year, as shown below:
- 2023: $66,000
- 2022: $61,000
- 2021: $58,000
- 2020: $57,000
- 2019: $56,000
- 2018: $55,000
- 2017: $54,000
- 2016: $53,000
Do I Need to Contribute to a Solo 401k Every Year?
No, you do not need to contribute to your Solo 401k plan every year. Your account will generally remain open and in good standing, even if you skip a year — as long as you meet any ongoing plan or reporting requirements. That said, if you plan to not contribute for several years, it may be best to wind it down to avoid unnecessary annual costs.
Contribution amounts are flexible, and depending on your plan provider, you may be able to choose between Roth and pre-tax contributions.
Tax Deduction Limits
While Roth Solo 401k contributions are not tax deductible, traditional pre-tax Solo 401k contributions can lower your annual taxable income. Both employee and employer contributions made with pre-tax dollars may count toward your total tax deduction, up to the applicable contribution limit.
✏️ For example:
- For 2025, you may be eligible for a tax deduction of up to $70,000, or $77,500 if you’re age 50 or older, depending on your income, business structure, and contribution type.
- For 2024, you may be eligible for a tax deduction of up to $69,000 or $76,500 if you’re age 50 or older.
📝 Note: Not all Solo 401k plans include a Roth option. It’s important to review your provider’s features to understand what types of contributions are available.
Frequently Asked Questions
Below are some common questions about Solo 401k contribution limits and deadlines for 2024 and 2025.
What Is the Solo 401k Contribution Limit for 2025?
The Solo 401k combined contribution limit for 2025 is $70,000. If you’re age 50 or older by December 31, 2025, you may qualify for an additional $7,500 in catch-up contributions, bringing the total to $77,500.
What Is the Solo 401k Contribution Limit for 2024?
For 2024, the total combined contribution limit is $69,000. If you’re age 50 or older by December 31, 2024, you may be eligible for an additional $7,500, raising the total to $76,500.
📌 Use our solo 401k contribution calculator to determine your contribution room.
How Do Contributions Work for a Solo 401k?
A Solo 401k allows eligible individuals to contribute as both the employee and the employer.
- Employees can contribute up to $23,500 for 2025 and $23,000 for 2024.
- Employer contributions are generally based on a percentage of compensation — up to 25% if the business is incorporated, or around 20% of net earnings if it’s not incorporated.
Can I Choose to Contribute as Pre-tax or Roth?
In many cases, you may be able to choose how much to allocate to either a pre-tax or Roth account. However, not all Solo 401k plans include a Roth option, so it’s important to review your provider’s features before deciding.
Before 2023, only employee contributions could be Roth, while employer contributions had to be pre-tax. The SECURE 2.0 Act now allows both to be Roth if your plan permits it.
What’s the Difference Between Pre-tax and Roth Contributions?
Some Solo 401k plans may offer both a pre-tax and Roth account, depending on the provider. They generally work the same way as a traditional and Roth IRA.
- In a pre-tax Solo 401k, your contributions could lower your taxable income and grow tax-deferred. When you withdraw money in retirement, it’s taxed as ordinary income.
- In a Roth Solo 401k, you contribute after-tax dollars, so you don’t get an immediate tax break, but your withdrawals are tax-free.
What Is the Solo 401k Contribution Deadline?
The deadlines differ for employee and employer contributions:
✅ Employee contributions:
- You’ll typically need to file your election by December 31 and fund your account up to April 15 of the following year.
✅ Employer contributions:
- Employers running a sole proprietorship, C corporation, or LLC taxed as a sole proprietorship have until the federal tax filing deadline (April 15).
- Employers running a partnership, S corporation, or LLC taxed as a corporation have until March 15.
- Employers may request a tax extension, which, if approved, generally allows an additional six months to make contributions beyond the original deadlines.
Looking to open a Solo 401k plan? Get started today with just a few clicks – The Carry Solo 401k Plan is a feature-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.📌 Need clarity on Solo 401k contributions? Learn about employee vs. employer contributions, the right bank account to use, and how to avoid over-contributions.
Disclosures:
The accounts, strategies and/or investments discussed in this material may not be suitable for all investors. All investments involve the risk of loss, and past performance does not guarantee future results. Investment growth or profit is never a guarantee. All statements and opinions included on the Carry Learning Center are intended to be current as of the date of publication but are subject to change without notice.
To access investment advisory services through Carry Advisors, you must be a client of Vibes on an eligible membership plan. For more information about Carry Advisors’ investment advisory services, please see our Form ADV Part 2A brochure and Form CRS or through the SEC’s website at www.adviserinfo.sec.gov.
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Disclaimer
The Carry Learning Center is operated by The Vibes Company Inc. (“Vibes”) and contains generalized educational content about personal finance topics. While Vibes provides educational content and technology services, all investment advisory services discussed on this website are provided exclusively through its wholly-owned subsidiary, Carry Advisors LLC (“Carry Advisors”), an SEC registered investment adviser. The information contained on the Carry Learning Center should not be construed as personalized investment advice and should not be considered as a solicitation to buy or sell any security or engage in a particular investment, accounting, tax or legal strategy. Vibes is not providing tax, legal, accounting, or investment advice. You should consult with qualified tax, legal, accounting, and investment professionals regarding your specific situation.
The accounts, strategies and/or investments discussed in this material may not be suitable for all investors. All investments involve the risk of loss, and past performance does not guarantee future results. Investment growth or profit is never a guarantee. All statements and opinions included on the Carry Learning Center are intended to be current as of the date of publication but are subject to change without notice.
To access investment advisory services through Carry Advisors, you must be a client of Vibes on an eligible membership plan. For more information about Carry Advisors’ investment advisory services, please see our Form ADV Part 2A brochure and Form CRS or through the SEC’s website at www.adviserinfo.sec.gov.