If you have spare money and a loan outstanding, it's a reasonable question whether that money is better used to prepay the loan or to invest it elsewhere. There's no universal answer, but there is a useful way to frame the comparison.
The core comparison: loan rate vs realistic investment return
Prepaying a loan guarantees you avoid paying that loan's interest rate on the amount prepaid for the rest of its term. In that sense, it behaves like a risk-free, guaranteed return equal to your loan's interest rate. Investing instead exposes that same money to market returns, which could be higher or lower, and are never guaranteed.
A simple starting framework: if your loan's interest rate is higher than the realistic, after-tax return you'd expect from investing over a similar time horizon, prepayment is generally the more certain financial choice. If your loan's rate is lower than what you'd reasonably expect to earn investing, continuing to invest - while still paying your loan as scheduled - can make more sense, though it carries market risk a prepayment doesn't.
Why "guaranteed" matters more than people think
A loan's interest rate is fixed and certain (or at least known today, for floating-rate loans). Investment returns are not - they can be negative in a given year, and even long-term averages are estimates, not promises. This is why many financial planners suggest valuing the certainty of a prepayment slightly higher than its raw interest rate would suggest on paper, as a form of risk-adjustment.
Factors that can tip the decision either way
- Employer retirement matching. If your employer matches retirement contributions, that match is close to an immediate, guaranteed return that's hard for a prepayment to beat - prioritising enough contribution to capture the full match is usually worth doing before extra prepayment.
- Emergency fund status. Don't prepay or invest with money you might need on short notice - build a basic emergency fund first, regardless of which option you lean towards afterwards.
- Loan prepayment charges. A charge reduces the effective "return" of prepaying, which can shift the comparison towards investing instead. See our guide on prepayment charges and rules.
- Your own risk tolerance. Some people simply prefer the certainty of a shrinking loan balance over market exposure, even when the math is close - that's a legitimate personal preference, not a mistake.
A blended approach is common
Many people don't choose one option exclusively - they continue essential or matched investing while also directing some extra funds towards prepayment, particularly on higher-rate debt. There's no rule that says it has to be all-or-nothing.
Key takeaways
- Compare your loan's interest rate to a realistic (not optimistic) after-tax investment return as a starting point.
- A prepayment's "return" is guaranteed; an investment's return is not - that certainty has real value.
- Capture any employer retirement match before prioritising extra prepayment, if that applies to you.
- A blended approach - some investing, some prepayment - is common and reasonable.
This is general information, not personalised financial advice - everyone's situation, risk tolerance and goals differ, so consider speaking with a qualified financial advisor for guidance specific to you.
Frequently asked questions
Is prepaying a loan the same as a guaranteed investment return?
Prepaying a loan guarantees you avoid paying that loan's interest rate on the amount prepaid - in that narrow sense, it behaves like a risk-free return equal to the loan's rate. It's not literally an investment product, but the comparison to a guaranteed return is a useful way to weigh it against other options.
Should I stop investing entirely to prepay my loan faster?
Not usually, especially if you have an employer retirement match (which is close to free money) or if your loan's interest rate is relatively low. A blended approach - continuing essential investing while also making some prepayments - is common. This isn't personalised financial advice; consider your full situation.
What if I'm not sure what return my investments will realistically earn?
Use a conservative, realistic long-term estimate rather than an optimistic one, and remember investment returns aren't guaranteed the way a prepayment's 'return' is. When in doubt, the certainty of a prepayment has real value beyond just the raw numbers.