Why Paying Off $80K in Student Loans Could Cost You $500,000

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By Michael Williams Published

Quick Read

  • Austin Hankwitz argues investing $80,000 instead of paying off a 5.35% loan could grow it to $640,000 over 20 years via compounding.

  • Your debt's interest rate determines the right move. Federal loans at 4 to 6% favor investing, while rates above 8% typically favor payoff.

  • Advisory fees of 1.25% from firms like Edward Jones silently erode decades of compounding, making low-cost platforms like Fidelity a better choice.

  • Many financial professionals are salespeople paid on what they push, not whether you end up wealthier. A fiduciary is the opposite. The SEC legally requires them to put your interests first. Advisor.com's free matching tool pairs you with vetted fiduciaries from major national firms, all in under three minutes. See who you match with today.

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Why Paying Off $80K in Student Loans Could Cost You $500,000

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On a recent episode of the Rich Habits Podcast, co-host Austin Hankwitz took a listener’s question about a $130,000-a-year household carrying $80,000 in student loans at 5.35% interest and delivered a blunt verdict: “Paying off debt only goes to zero.” His argument was that shoveling every extra dollar at a low-rate loan is one of the more expensive mistakes a young investor can make. According to Hankwitz, that same $80,000 left in the market “gonna double now every 7 years to $160,000, $320,000, $640,000”, so twenty years later “that $80,000 is now half a $500,000.”

If the listener follows the aggressive-payoff instinct instead, the real cost is a two-decade head start on compounding that never gets rebuilt.

The Verdict: He Is Right, but the Rate Is Doing the Work

Hankwitz’s advice is sound for this specific borrower, and the mechanism is opportunity cost. Every dollar sent to a 5.35% loan earns a guaranteed 5.35% return. Every dollar invested in a diversified equity index earns whatever the market delivers, which historically has been higher over long stretches. The doubling-every-seven-years figure is his projection, not a guarantee, but the underlying market data gives it a plausible anchor. The S&P 500 tracked by the SPDR S&P 500 ETF Trust (NYSEARCA:SPY) has returned roughly 241% over the past ten years and about 485% over the past twenty. Those returns comfortably exceed the loan rate.

Consider a simplified illustration using Hankwitz’s own numbers. He frames $80,000 doubling every seven years to $160,000, then $320,000, then $640,000. Even a lower assumed return would clear the 5.35% hurdle. Stocks may not replicate the past, but a guaranteed 5.35% payoff return is a low bar when the alternative asset class has historically delivered far more, and when the borrower has twenty-plus years of runway to ride out drawdowns.

Compare that to the risk-free alternatives sitting on the table today. The 10-year Treasury yields about 4.7%, I-bonds pay a combined rate near 4.3%, and the national average 12-month CD sits near 1.7%. None of those beat 5.35% on a guaranteed basis, which is why the answer here hinges on equities, not cash.

The Variable That Flips the Math

The single factor that decides whether Hankwitz’s advice helps or hurts a reader is the interest rate on the debt.

At 5.35%, the spread over safe yields is thin and the spread under long-run equity returns is wide. Investing wins on expectation. Flip the rate to 22% on a credit card, and the calculus inverts instantly. No diversified portfolio reliably clears a 22% hurdle, so every dollar sent to that balance is the best return available. The rule of thumb: if the debt rate is comfortably below your realistic long-run investment return, invest. If it is above, pay it off. Federal student loans in the 4% to 6% range typically fall on the investing side, especially inside tax-advantaged accounts. Private loans above 8% often do not.

The Fee Drag Nobody Sees

Robert Croak added a second warning on the same episode. He said Edward Jones, “is going to sell you what they make the most money on” and charges roughly 1.25% in fees. On a portfolio meant to compound for decades, a 1.25% annual haircut is not a rounding error. It quietly eats a meaningful share of the doubling Hankwitz described, because it comes out every year regardless of returns.

What to Actually Do

The hosts laid out a specific blueprint for the $130,000 earner with a mortgage and a new baby:

  1. Contribute 5% to the employer 401(k) to capture the full 4% match, roughly $541 a month. The match is an immediate 100% return on the matched portion. Nothing else in this article comes close.
  2. Max both Roth IRAs at $625 a month each, totaling $1,250 a month. Tax-free growth for decades.
  3. Move brokerage assets off a 1.25% advisory platform to a self-managed account at Fidelity or Public. Keep total monthly contributions near $1,800.
  4. For the baby, open a 529 and a Trump account to capture $1,000 in free money and contribute up to $5,000 a year.
  5. Do not make extra payments on the 5.35% student loans until the equivalent balance is invested. Pay the minimum, on time, every month.

The takeaway: at a 5.35% rate, the real emergency is the missed decade of compounding.

Contact [email protected] for any questions or corrections.

Photo of Michael Williams
About the Author Michael Williams →

I am a long time investor and student of business, and believe finding good companies that can become great investments is the best game on earth. After 20 years of writing and researching the public markets it is clear that individuals have never had more tools and information to take control of their financial lives. From ETFs and $0 commissions to cryptos and prediction markets there has never been a greater democratization of access to investing. 

I write to help people understand the investments available to them so they can make the best choice for their portfolio, whether they're starting out or looking for income in retirement. 

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