How a 401(k) Works
When you enroll in your company's 401(k) plan, you choose a percentage of your salary to contribute. This money is automatically taken from your paycheck before income taxes are calculated, which lowers the amount of taxes you owe that year. You decide how to invest your contributions among options like stock funds, bond funds, and money market funds provided by your employer's plan.
Employer Matching
Many employers offer to match a portion of your contributions as an employee benefit. For example, a company might match 50% of what you contribute up to 6% of your salary. This is free money that goes directly into your account, and it's one of the biggest advantages of 401(k) plans. You should contribute enough to get the full employer match if your company offers it.
Investment Growth
Your 401(k) money is invested based on your chosen allocation among different funds. Over time, your contributions and any employer match grow through investment returns. The longer you leave money in the account, the more time it has to grow through compound interest, which is why starting early is beneficial for retirement savings.
Withdrawals and Taxes
You generally cannot withdraw money from your 401(k) before age 59 and a half without paying a 10% penalty plus income taxes on the withdrawal. When you do withdraw money in retirement, you pay income taxes on the amounts you withdraw, since the original contributions were made with pre-tax dollars. This means you pay taxes when you use the money, not when you save it.
Vesting
Vesting is the process of earning ownership of employer contributions to your account. Some employers give you immediate ownership of their matching contributions, while others require you to work there for a certain number of years before you fully own the employer's contributions. Your own contributions are always yours immediately.
Leaving Your Job
If you change jobs, you have several options for your 401(k) balance. You can leave the money in your former employer's plan if your balance is large enough, roll it over to your new employer's 401(k) if available, or roll it into an Individual Retirement Account (IRA). Rolling over your account allows your money to continue growing without taxes or penalties.