Solo 401k Contribution Limits 2024. For 2023, that maximum is $66,000, or $73,500 if the additional $7,500 is deferred. Starting in 2024, employees can contribute up to $23,000 into their 401 (k), 403 (b), most 457.

And the limit goes up to $66,000 in 2023. The limits are the same as for the solo 401(k):