2028 Solo 401(k) Limit
2028 Solo 401(k): up to $73,500 owner-only ($82,000 if 50+, $85,250 if 60-63 super-catch-up). Combines employee elective + employer profit-sharing.
| Compensation | — |
| Employee elective | — |
| Employer profit-share | — |
| Effective % of comp | — |
| Total 2028 Solo 401(k) | — |
The 2028 Solo 401(k) limit is projected at $73,500 total ($82,000 with catch-up at 50+, $85,250 with super-catch-up at 60-63). Combines employee elective ($24,500) with employer profit-sharing (25% S-corp / ~20% sole prop). Owner-only — no employees besides spouse.
Why Solo 401(k) Wins Owner-Only
Same overall $73,500 (projected 2028) cap as SEP IRA, but Solo 401(k) allows $24,500 employee deferral regardless of income. Owner with $100k W-2: SEP = $25k. Solo 401(k) = $24,500 + $25,000 = $49,500. Solo wins for any owner-only setup. SEP requires high income to hit $73,500 cap.
Catch-Up Layers
Standard catch-up at 50+: +$8,000. Super-catch-up at 60-63 (SECURE 2.0): +$11,250 instead of $8,000. At age 60-63, total Solo possible = $24,500 + $11,250 + $46,500 employer = $82,250. Window of 4 years to max — once 64, back to standard catch-up.
Roth Solo 401(k)
SECURE 2.0 (2024+) allowed employer profit-share to be Roth (post-tax). Previously employee only. High earners over $145k W-2: super-catch-up must be Roth per SECURE 2.0 mandate. Bring tax planning forward.
Spouse on Payroll
Spouse working in the business doubles the contribution capacity: $147,000 total household for couple under 50. Spouse must be legitimately employed with paid wages. Real services rendered. Common audit trigger if fake.
Last updated May 2026. Sources: IRS Solo 401k.