A woman is 50, has $300,000 in her 401(k), and wants to renovate her kitchen. Her plan looks straightforward on paper: borrow $50,000 from the plan, repay it over five years at 7% via payroll deduction, and keep the interest flowing back to herself. No bank, no credit check, no application. I would tell her to walk away from that loan. The reason has almost nothing to do with the 7% rate.
The real cost is closer to $100,000 of retirement balance she will never see, and it surfaces in two places most borrowers never run the math on.
The principal that stops working for five years
When that $50,000 leaves the account, it stops compounding inside the 401(k). The interest she pays herself sounds like a clever workaround, but it is paid with after-tax dollars and then taxed again as ordinary income when she withdraws it in retirement. That is the double-tax quirk of 401(k) loan interest that almost no plan participant has had explained to them.
The opportunity cost is the bigger number. $50,000 left invested for 15 years at a 7% growth assumption compounds to roughly $138,000 by age 65. The same $50,000, repaid by year five and then reinvested for the remaining 10 years, lands closer to $98,000. That gap is about $40,000, and it exists even if she does everything else right.
For context on what a 7% assumption means, the SPDR S&P 500 ETF Trust (NYSEARCA:SPY) has returned roughly 22% over the past 12 months and more than 315% over the past decade. Long-run averages are lower, but pulling $50,000 out of equities for five years of a strong cycle is a costly way to fund a kitchen renovation.
The match she stops earning while paying herself back
The quieter damage is the contribution pause. Most borrowers cannot fit the loan repayment and full salary deferrals into the same monthly cash flow, so they cut contributions and forfeit the employer match. A $5,000 annual match missed from age 50 through 54, compounded at 7% to age 65, adds up to roughly another $60,000 of forgone balance. Each year’s missed deposit grows for a different horizon, and the earliest year lost matters most.
Add the two together, and the loan that felt free costs her about $100,000 of retirement balance at 65. That is real money, and it lands precisely when she has the least time to recover it.
The job-loss trapdoor nobody warns you about
A third risk is binary rather than mathematical. If she leaves her employer or is terminated before the loan is fully repaid, the outstanding balance is treated as a deemed distribution. The full amount becomes taxable as ordinary income, and the 10% early withdrawal penalty applies if she is under 59.5. On a $35,000 outstanding balance, that can mean a five-figure tax bill arriving in the same year she just lost her income. The IRS confirmed these rules hold in 2026, with the $50,000 loan ceiling still fixed by statute and not adjusted for inflation.
The macro backdrop adds its own weight. The University of Michigan Consumer Sentiment Index reached a preliminary reading of 54.4 in July 2026, rebounding from a record-low 44.8 in May but still roughly 12% below where it stood a year ago. Meanwhile, the personal savings rate has compressed sharply: BEA data show the household savings rate at 3% as of May 2026, down from the low-to-mid-4% range two years prior. Layoffs in a soft economic cycle are exactly when deemed distributions hit hardest, and households with thin buffers have no room to absorb one.
What I would do instead
- Price a HELOC or 0% promotional credit first. With the 10-year Treasury recently near 4.55% and the effective federal funds rate at 3.63%, home equity lines are not cheap, but the interest is potentially deductible if the renovation qualifies, and the retirement principal stays invested. A 0% promotional card on a smaller scope of work can bridge 12 to 18 months without touching the 401(k).
- If you take the loan anyway, do not cut contributions. Run the household budget so payroll deferrals stay at the level that captures the full employer match. Losing the match is what turns a $40,000 mistake into a $100,000 one.
- Treat the 401(k) loan as the last option, not the easy one. Anchor the decision to the deemed-distribution risk: if there is any realistic chance of a job change in the next five years, the loan is the wrong tool.
If the renovation budget is tight enough that a 401(k) loan looks attractive, that is usually the signal to shrink the project, not the retirement account. With inflation running at 3.5% annually through June 2026, still well above the Fed’s 2% target, the dollars pulled out today buy less by the time they are repaid. Compare quotes from a fee-only advisor through SmartAsset before signing the paperwork. The hour of math is cheaper than the $100,000.
Editor’s note: This update refreshes the University of Michigan Consumer Sentiment figure to the preliminary July 2026 reading of 54.4 (up from the prior 53.3 figure and from the record-low 44.8 in May), updates the U.S. personal savings rate to the BEA’s May 2026 reading of approximately 3%, corrects SPY’s 1-year return to roughly 22% and its 10-year cumulative return to more than 315%, and revises the 10-year Treasury yield to approximately 4.55% and the effective federal funds rate to 3.63%; the June 2026 CPI reading of 3.5% is also cited as the current inflation backdrop.
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