Understanding the difference between retirement plans like 401k, 401a, and 403b is crucial for financial planning. 401k and 403b are employer-sponsored plans, while 401a is typically for profit-sharing or employee stock ownership plans. 401k vs 403b: 401k plans are more common in private companies, while 403b is for educators and certain public employees. Both offer tax benefits, but contribution limits, investment options, and eligibility may vary.