Pay Off Student Loans or Invest? Here's a Way to Run the Math

If you carry student loans, you're in big company. About 42.8 million Americans owe roughly $1.8 trillion in federal student debt, and the average balance sits near $39,500. So whether to pay off student loans or invest is a question many people quietly wrestle with, on top of covering their essentials, such as rent, food, and building their emergency fund.

Here's the reassuring part: This isn't an all-or-nothing choice. In most cases you can do a little of both. This guide walks through the one comparison that drives the decision, shows you the math with a plain dollar example, and lays out the order of moves that lets you make progress on your loans and your future at once.

If you want to go deeper on the growth side, it helps to understand how compound interest works first.

The one comparison that drives the decision

Whether you should pay off student loans or invest comes down to a single comparison: Your loan's interest rate versus the return you expect from investing. If your loan rate is higher than your expected return, paying the loan down faster is the stronger move, because you're locking in a guaranteed return equal to your rate. If your loan rate is lower than what you can reasonably expect to earn, you could invest a bit more.

That makes your interest rate the number to know. For loans taken out in the 2025-26 school year, the federal undergraduate rate is 6.39%, the graduate rate is 7.94%, and PLUS loans are 8.94%. Loans first disbursed on or after July 1, 2026 carry slightly higher rates, such as 6.52% for undergraduates. You can look up the current federal student loan rates on the federal student aid site.

A rough rule of thumb: Debt above 7% or 8% is considered on the higher end and usually worth prioritizing, while debt at around 4% to 6% is low enough that investing alongside your payments often makes sense. There's no magic cutoff, which is exactly why the comparison matters more than any single rule. For a faster-payoff game plan, see our guide on how to pay off student loans fast.

Why a guaranteed return isn't the same as an expected one

Paying off a loan gives you a guaranteed return, while investing gives you an expected but uncertain one. When you pay extra on a 6.39% loan, you save 6.39% in interest you would have owed, every time, no matter what the market does. That return is locked in.

Investing is a little different. Historically, the S&P 500 has returned about 10% a year on average over the long term, but that figure comes with real caveats. It's an average across decades, but past performance doesn’t guarantee future results. Because of that uncertainty, it's smart to use a more conservative estimate, say 8%, when you run your own numbers, and that a guaranteed 6.39% saved can be worth more than a hoped-for 10% earned. For a plain-language primer, the SEC's investor.gov has a helpful explainer on long-term investing and compound interest.

A plain dollar example

Here's what the choice can look like in actual dollars. Say you have an extra $100/month and a 10-year window. Using a hypothetical 8% return for investing and a 6.39% undergraduate loan rate for payoff, here's roughly how each path plays out:

• All $100 toward investing is about $18,300 total. You'd put in $12,000 of your own money, and at a hypothetical 8% return, the rest would be growth.
• All $100 toward your loan is about $16,700 in guaranteed value, since every dollar paid early erases 6.39% interest you'd otherwise owe.
• Split $50 and $50 is about $17,500 total, with roughly half invested and half knocked off your balance.
   

The investing path edges ahead here because the expected 8% return beats the 6.39% loan rate. But notice two things. The gap is smaller than people expect, and the payoff side is the only one that's guaranteed. That's why a split is a more popular option: It captures some of investing's higher potential while still shrinking your debt. These are hypothetical figures, not guarantees, and your real numbers depend on your rate, your timeline, and how markets perform.

Your guide to navigating debt and investing

Before the pay-off-or-invest question even applies, a few moves come first, because they beat both options on a pure dollar basis. Here's the order most financial educators suggest:

1. Build a small emergency fund. A starter cushion of even $500 to $1,000 can keep a surprise expense from landing on a high-interest credit card. You can build an emergency fund gradually while you sort out the rest.

2. Capture any employer 401(k) match. If your job matches retirement contributions, that's an immediate, guaranteed return, often 50% to 100% on the matched amount. It's the closest thing to free money in personal finance, so try not to leave it on the table.

3. Knock out high-interest debt. Credit cards and other debt above roughly 10% should come before extra student loan payments or investing, since that interest almost certainly outpaces what you'd earn. The debt avalanche method (highest rate first) saves the most, while the debt snowball (smallest balance first) can feel more motivating.
    

Only after meeting these 3 does the loan-versus-invest comparison really take center stage. If your emergency fund has been built, your match is captured, and your high-interest debt is gone, you're in a great spot to make the call.

You don't have to choose just one

For most people, the best answer to the pay-off-or-invest question is doing both. Making your regular loan payments while investing small amounts at the same time means your balance shrinks and your money has a chance to grow.

This is where starting small can do a lot of work. You don't need a big lump sum to begin investing. With Acorns Invest, you can automatically invest your spare change with Round-Ups®, which round up your everyday purchases and put the difference into an expert-built, diversified portfolio. You can layer on a Recurring Investment, even just a few dollars a week, so investing happens in the background while you stay current on your loans. Over time, those small, steady amounts add up, which is the whole idea behind giving your money a chance to grow.

What the math leaves out

The rate-versus-return rule is the backbone of the decision, but a few non-math factors can also be worth considering:

• Peace of mind. Some people sleep better with less debt. If your loans cause you a lot of stress, paying them down faster would be the simplest answer.

• Time horizon and age. The longer your money can stay invested, the more time it has to tap into compounding.

• Forgiveness and repayment plans. If you're pursuing student loan forgiveness or are on an income-driven plan, paying extra may not make sense, since you could be working toward having a balance forgiven anyway.

• Job stability. If your income feels shaky, a larger cash cushion and lower fixed payments could help more.
   

It's also worth knowing that federal repayment is changing. Under the One Big Beautiful Bill Act, a new Repayment Assistance Plan is replacing several older income-driven plans for many borrowers, with most changes taking effect in mid-2026. The specifics are still being settled, so check the federal student aid site for where your loans stand before making a long-term plan.

On taxes, keep it high level. The student loan interest deduction can lower the effective cost of your loans, and investment or retirement accounts can offer potential tax advantages. A Roth IRA, for example, has tax-free growth potential in retirement, which can make investing more attractive. If that fits your goals, you can open a Roth IRA and invest for retirement at the same time you're paying down debt. This is general information, not tax advice, so a tax professional can help with your specifics.

So, should you pay off student loans or invest? You don't have to wait until your loans are gone to start building wealth. Start investing while you pay down debt with Acorns.

Frequently asked questions

Should I pay off my student loans or invest?

It depends on one comparison: Your loan's interest rate versus the return you expect from investing. If your loan rate is higher than your expected return, paying it down faster is a better option. If it's lower, you can put more towards investing. For many people, a split between the two is the most comfortable answer.

Is it better to pay off student loans early?

Paying off student loans early is often worth it when your interest rate is high, roughly 7% or above, because you lock in a guaranteed return equal to your rate. When your rate is lower, around 4% to 6%, the guaranteed savings are smaller, and investing alongside your regular payments can leave you better off over time. It also comes down to how much debt-free peace of mind matters to you.

What interest rate makes it better to invest instead of paying off loans?

There's no single cutoff, but a useful guideline is your expected investment return. If your loan rate is comfortably below the return you reasonably expect, often estimated at a conservative 8%, investing usually makes sense. If your loan rate is at or above that, leaning toward payoff is the safer bet, since the return on paying down debt is guaranteed and the return on investing is not.

Can I pay off student loans and invest at the same time?

Yes, and many people do. Making your regular loan payments while investing small amounts automatically lets you shrink your balance and gives your money a chance to grow at once. Tools like Round-Ups® and a Recurring Investment with Acorns make it easy to invest a few dollars at a time in the background while you stay current on your loans.

What should I do before choosing between paying off loans and investing?

Cover three things first: build a small emergency fund, capture any employer 401(k) match, and pay off high-interest debt like credit cards. Each of those beats both extra loan payments and investing on a dollar basis. Once they're handled, the loan-versus-invest comparison is where your extra money should go.