Self-employed? A solo 401(k) and a SEP IRA both allow up to $72,000 in 2026, but they differ on how fast you get there, Roth options, deadlines, and the backdoor Roth.

Leaving a job? Your 401(k) can stay, move to a new plan, roll into an IRA, convert to Roth, or be cashed out. Here's how each option works and what it costs.