The Moment
You have a car loan at 5%, student loans at 6%, or a mortgage at 4.5%. You also have money available to either accelerate debt payoff or invest. Unlike the high-rate case (always pay debt) or the low-rate case (usually invest), the 4-7% range is genuinely a coin flip.
The Math (It Is Close)
$10,000 toward 6% debt: Guaranteed 6% return. After 10 years: $17,908 in saved interest and principal.
$10,000 invested at 7% average: Expected 7% return. After 10 years: $19,672 (expected, not guaranteed).
Difference: ~$1,764 — roughly 1% per year edge for investing. But investing carries risk: in a bad decade (5% returns), investing underperforms. In a good decade (10% returns), investing wins convincingly.
The answer depends on you: - Math-optimizers: Invest. The expected return edge, while small, compounds over time. Accept the volatility as the price of the higher expected return. - Peace-of-mind seekers: Pay the debt. The stress relief of being debt-free has behavioral value that the math does not capture. You will sleep better, make better financial decisions, and feel more secure. - Everyone: Capture your 401(k) match first. A 50-100% match beats any other option regardless of debt rate.
Run Your Numbers
Compare the returns.
Compound Growth Projector
What to explore next
- →Should I pay off my car loan or invest?
- →How do I decide between mortgage payoff and investing?
- →What if my debt is at exactly 5%?
Frequently Asked Questions
Can I do both — pay some and invest some?
Yes, and this is a perfectly valid approach in the gray zone. Split extra money 50/50 between debt and investing. You get partial benefit from both — some guaranteed return from debt payoff and some market exposure from investing. It is not mathematically optimal for either scenario, but it is psychologically comfortable for many people.