Your Retirement account options Solo 401(k), SEP IRA, SEP 401(k), and Individual 401(k)

Income limitation to invest: None, but there are income limits for tax-deductible contributions if you or your spouse are covered by a retirement plan at work.
Maximum contribution: $6,000 (2022), or $7,000 if age 50 or older.
Who can contribute: Anyone with earned income.
Who cannot contribute: Individuals who are age 72 or older and those who do not have earned income.
Penalties for overfunding: 6% excise tax on excess contributions.
What to do if you overfunded: Withdraw the excess contributions and any earnings on them by the tax deadline, or incur a 6% excise tax each year the excess remains in the account.

Income limitation to invest: $140,000 (single) or $208,000 (married filing jointly) for full contribution, with phase-out limits up to $155,000 (single) or $298,000 (married filing jointly).
Maximum contribution: $6,000 (2022), or $7,000 if age 50 or older.
Who can contribute: Anyone with earned income within the income limits.
Who cannot contribute: Individuals with income above the phase-out limits.
Penalties for overfunding: 6% excise tax on excess contributions.
What to do if you overfunded: Withdraw the excess contributions and any earnings on them by the tax deadline, or incur a 6% excise tax each year the excess remains in the account.

Income limitation to invest: None.
Maximum contribution: $20,500 (2022), or $27,000 if age 50 or older.
Who can contribute: Employees of companies that offer a 401(k) plan.
Who cannot contribute: Self-employed individuals and those who do not have access to a 401(k) plan.
Penalties for overfunding: 10% excise tax on excess contributions.
What to do if you overfunded: Withdraw the excess contributions and any earnings on them by April 15 of the following year, or incur a 10% excise tax.

Income limitation to invest: None.
Maximum contribution: $6,000 (2022), or $7,000 if age 50 or older.
Who can contribute: A non-working spouse of an individual with earned income.
Who cannot contribute: Individuals without earned income or those who file separately.
Penalties for overfunding: Same as Traditional or Roth IRA.
What to do if you are overfunded: Same as Traditional or Roth IRA.

Self-Employed Individuals -

Income limitation to invest: None.
Maximum contribution: $20,500 (employee elective deferral) + 25% of compensation (employer profit sharing contribution) up to a total of $58,000 (2021) or $61,000 (2022), or $64,500 (2021) or $68,000 (2022) if age 50 or older.
Who can contribute: Self-employed individuals with no employees other than a spouse, or with employees who are not eligible to participate in the plan.
Who cannot contribute: Self-employed individuals who have common-law employees who are eligible to participate in the plan.
Penalties for overfunding: Same as 401(k).
What to do if you are overfunded: Same as 401(k).

Income limitation to invest: None.
Maximum contribution: 25% of compensation up to a total of $58,000 (2021) or $61,000 (2022).
Who can contribute: Self-employed individuals and small business owners with one or more employees.
Who cannot contribute: Employees who have not met the eligibility requirements.
Penalties for overfunding: 6% excise tax on excess contributions.
What to do if you overfunded: Withdraw the excess contributions and any earnings on them by the tax deadline, or incur a 6% excise tax each year the excess remains in the account.

Income limitation to invest: None.
Maximum contribution: $20,500 (employee elective deferral) + 25% of compensation up to a total of $58,000 (2021) or $61,000 (2022), or $64,500 (2021) or $68,000 (2022) if age 50 or older.
Who can contribute: Self-employed individuals and small business owners with one or more employees.
Who cannot contribute: Employees who have not met the eligibility requirements.
Penalties for overfunding: Same as 401(k) and SEP IRA.
What to do if you are overfunded: Same as 401(k) and SEP IRA.