What Is a 401(k) Loan and When Should You Use One?

When you need cash and you have a 401(k), it's tempting to borrow from it. You're borrowing your own money, after all — and you pay yourself back with interest. It sounds like a free loan. But 401(k) loans come with significant hidden costs that aren't obvious at first glance.

How 401(k) Loans Work

Most 401(k) plans allow you to borrow up to 50% of your vested balance, or $50,000, whichever is less. You repay the loan through payroll deductions over up to 5 years (longer for a primary home purchase). The interest rate is typically the prime rate plus 1–2%, and the interest goes back to your own account — not to a lender.

The Real Costs of a 401(k) Loan

• Opportunity cost: The borrowed money isn't invested and misses market growth. Borrow $20,000 when the market returns 8% that year and you miss $1,600 in growth.
• Double taxation on interest: You repay the loan with after-tax dollars, then pay taxes again on those same dollars in retirement.
• Risk of job loss: If you leave your job, the full remaining balance is typically due by the tax-filing deadline for that year (extended from the old 60-day rule by the Tax Cuts and Jobs Act). If you can't repay in time, it's treated as a distribution — income taxes plus a 10% early withdrawal penalty if you're under 59½.
• Contribution disruption: Many people stop contributing to their 401(k) while repaying the loan, losing both the employer match and compounding growth.

When a 401(k) Loan Makes Sense

• You have a genuine financial emergency and no other options (no emergency fund, can't qualify for other loans).
• You're confident you'll stay at your employer until the loan is repaid.
• The alternative is high-interest debt (credit cards at 20%+) that you can't pay off quickly.
• You can maintain your 401(k) contributions while repaying the loan.

Even in the best case, a 401(k) loan costs you something. Because the borrowed money stops compounding the moment it leaves the account, a loan you repay perfectly on schedule still leaves your retirement balance smaller than if you had never touched it. The interest you pay yourself is almost always less than what the market would have returned over the same years — that gap is the real price, and you don't get it back.

Better Alternatives to a 401(k) Loan

• Emergency fund: The ideal solution — interest-free, no tax consequences.
• Personal loan: Often lower rates than credit cards, no impact on retirement savings.
• HELOC: Lower rates, but requires home equity and puts your home at risk.
• 0% APR credit card: For expenses you can pay off within the promo period.
• Roth IRA contributions: You can withdraw Roth IRA contributions (not earnings) at any time, penalty-free.

401(k) Loan vs. 401(k) Withdrawal

A 401(k) loan is almost always better than an early withdrawal. An early withdrawal triggers income tax on the full amount plus a 10% penalty — effectively costing 30–40% of whatever you take out. A loan avoids both, as long as you repay it. Only consider a withdrawal as a last resort in genuine hardship situations.