The Moment
You need money — for a down payment, medical bills, debt consolidation, or an emergency. Your 401(k) has $50,000+ in it, and you can borrow up to 50% (max $50,000). The interest rate is low (prime + 1%, typically 8-9%), and you are paying interest to yourself. Sounds reasonable, right?
It is not as good as it sounds. The "paying interest to yourself" framing hides the real cost: the compound growth your money would have earned if it stayed invested. That opportunity cost is the true price of a 401(k) loan.
The Hidden Costs
Cost 1 — Lost compound growth. $20,000 borrowed from a 401(k) at age 35 and repaid over 5 years loses approximately $25,000-$40,000 in growth by age 65 (at 7% returns). That is the true cost of the loan — not the 8% interest you are "paying yourself."
Cost 2 — The job change trap. If you leave your job (voluntarily or involuntarily), the outstanding 401(k) loan balance is due in full — typically within 60-90 days. If you cannot repay it, the outstanding balance is treated as a taxable distribution plus a 10% early withdrawal penalty if you are under 59.5. On a $20,000 loan, that is $5,000-$8,000 in taxes and penalties.
Cost 3 — Double taxation. 401(k) loan repayments are made with after-tax dollars. When you eventually withdraw the money in retirement, it is taxed again. You are taxed twice on the same money — something that does not happen with normal 401(k) contributions.
Cost 4 — Reduced contributions. Many people reduce or stop 401(k) contributions while repaying a loan. This compounds the growth loss and may cause you to miss employer match — free money you cannot recover.
When It Might Make Sense
A 401(k) loan is the least-bad option only if: - You face a genuine financial emergency (medical, imminent foreclosure) - The alternative is high-interest debt (payday loans, 25%+ credit cards) - You are confident you will not leave your job during the repayment period - You will continue making regular 401(k) contributions during repayment
In all other cases — home down payment, vacation, debt consolidation, car purchase — there are better alternatives: personal loans, HELOCs, saving longer, or adjusting your timeline.
Run Your Numbers
See how a 401(k) loan affects your retirement savings trajectory.
Retirement Savings Projector
What to explore next
- →What are the alternatives to a 401(k) loan?
- →How do I rebuild my 401(k) after taking a loan?
- →Should I take a 401(k) hardship withdrawal?
Frequently Asked Questions
Is a 401(k) loan better than a hardship withdrawal?
Yes, significantly. A hardship withdrawal is a permanent distribution: you pay income tax on the full amount plus a 10% penalty if under 59.5, and you can never put the money back. A loan at least preserves the possibility of repayment. If your only options are a 401(k) loan or hardship withdrawal, the loan is better.
Can I use a 401(k) loan for a home down payment?
Technically yes — the repayment period extends to 15 years for a primary residence purchase. But the opportunity cost remains. A $30,000 loan from a 401(k) at age 30 costs roughly $100,000+ in lost growth by age 65. If you can save the down payment over 12-18 months instead, the math strongly favors waiting.