Pay off debt or invest: which comes out ahead?
Under these assumptions, investing comes out $1,398 ahead: keeping the $15,000 loan where it is costs $1,636 more interest over 68 months than paying it down, while the $200 a month left to invest at an assumed 7% gains $3,034.
The worked example
A $15,000 student loan at 4% and $250 a month, committed either way. Pay the loan first: all $250 goes to it until it is gone. Invest first: the loan stays where it is, its $50 monthly interest is paid, and the other $200 is invested at an assumed 7% a year for the same months, with the loan still owed at the end. The two are compared on what is left: investments minus any debt. Below that, the same comparison for a $5,000 card at 22%.
| You put in | |
|---|---|
| Student loan | $15,000 |
| Loan APR | 4% |
| Monthly amount | $250 |
| Assumed annual return | 7%, before tax |
| Paying the loan | |
| Paying the loan: time to pay off | 68 months (about 5.7 years) |
| Paying the loan: interest | $1,764 |
| Investing instead, over the same months | |
| Investing: interest kept paid on the loan each month | $50 |
| Investing: put in each month | $200 |
| Investing: total put in | $13,600 |
| Investing: value at the end | $16,634 |
| Investing: gains | $3,034 |
| Interest the untouched loan charges | $3,400 |
| Extra interest over paying the loan down | $1,636 |
| Still owed at the end | $15,000 |
| Net advantage of investing instead | $1,398 |
| A $5,000 card at 22% instead | |
| Card: time to pay off | 26 months (about 2.2 years) |
| Card: put in each month after its interest | $158 |
| Card: investment gains over those months | $315 |
| Card: interest the untouched card charges | $2,383 |
| Card: extra interest over paying the card down | $1,097 |
| Card: net advantage of paying the card first | $782 |
Every figure on this page is computed from these inputs by the same calculator the channel’s Shorts use.
Run your own numbers
There is no calculator for this comparison on the site yet. These run each part with your own numbers:
- Credit card payoff calculator
Runs the debt side: any balance paid down with a fixed monthly amount.
- Compound interest calculator
Runs the investing side: a monthly amount growing at a rate you choose.
Educational content, not financial advice.
Next step
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Your next moves
Find your loan’s exact rate
It is on your loan statement, and the answer turns on it.
Run the loan side
A fixed monthly amount on a balance: the payoff calculator handles any debt.
Credit card payoff
How the comparison works
Both choices commit $250 a month for the same stretch: the 68 months that it takes to pay the loan off. Paying the loan, you pay $1,764 of interest along the way and end with no loan.
Investing instead, the loan is left where it is: its interest, $50 a month, is paid so the balance neither grows nor shrinks, which comes to $3,400 over those months, $1,636 more than paying it down costs. The other $200 a month goes into investments growing at an assumed 7% a year, compounded monthly, so $13,600 put in becomes $16,634, a gain of $3,034 before tax, sitting next to the $15,000 still owed. The result is that gain minus the extra interest.
What people get wrong
Comparing the two rates is where most people start, and it is only part of the story. The loan’s rate is certain; the market’s is an assumption, and real returns rise and fall from year to year. This example assumes the same 7% every year, which no investment guarantees.
The debt’s rate matters most. Run the same comparison on a $5,000 card at 22% and paying the card first comes out $782 ahead. Taxes, an employer match and the loan’s own terms can tilt the answer either way, and none of them is in this example.
It is also easy to forget that the loan does not shrink while you invest. At the end of the 68 months it is still $15,000, sitting next to a portfolio worth $16,634 that may be worth more or less by the time you would sell.
How to read the result
The net figure in the table is the investment gain minus the extra interest that leaving the loan untouched costs over paying it down. Here investing comes out $1,398 ahead under these assumptions; a higher loan rate or a lower return can flip it, and a loan rate equal to the return comes out even.
Read it as a sense of scale, not a forecast. A small gap means the choice turns on how you feel about risk and about carrying the loan; a large one in either direction is a clearer signal. The site has no calculator for this comparison yet, so the links above run each side on its own.
Questions
Is it better to pay off a student loan or invest?
It depends on the loan’s rate, the return you assume and your taxes. In this example, a 4% loan against an assumed 7% return, investing comes out $1,398 ahead over 68 months; on a 22% card, paying the card first comes out $782 ahead.
What return should I assume?
There is no safe answer: returns are not guaranteed and change from year to year. This example uses 7% a year before tax as an assumption, not a forecast.
What does the net advantage figure mean?
It is the investment gain minus the extra interest the untouched loan charges over the same months compared with paying it down, with the same $250 a month committed either way: $3,034 against $1,636, so investing comes out $1,398 ahead.
Interest compounds monthly at APR ÷ 12 and each payment lands at the end of the month, after that month’s interest. The same monthly amount is committed either way for the same months, and the two paths are compared on what is left at the end: investments minus any debt still owed. The investing case keeps the debt where it is, paying its interest each month, and invests the rest; returns are an assumption, compounded monthly and before tax. Disclaimer