A 401(k) loan is when you borrow money from your retirement savings account and repay it back to your account over a period, typically 12 months to five years. Most employer plans allow you to take out as much as 50% of your savings, up to $50,000, though plans can vary. There are some disadvantages, such as removing money from your account that would otherwise be growing tax-free, so be sure to research your options prior to doing this.