When planning for retirement, many ask what is a 401k benefits? A 401(k) is a retirement savings account offered through their employer that lets workers save a portion of their salary before taxes. Some of the most important 401k advantages include tax savings, having the employer match your contribution and building long-term wealth. The advantages of 401k become even better as investment money compounds over time. With knowledge of the advantages of 401k plans, individuals can plan for financial independence. On a high-level, the benefits of 401 k are disciplined savings, tax efficiency and retirement security.