Solo 401k Contribution Limits 2024. The irs maximum contribution to a solo 401k is $66,000 for 2023 (or $73,500 for those over age 50) and $69,000 for 2024 (or $76,500 for those over age 50). In 2023, you can contribute a maximum of $22,500 as an employee salary deferral contribution.

Find out how much you can contribute to your solo 401k with our free contribution calculator. In 2024, you can contribute $23,000 to the roth portion of your solo 401 (k).