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A guaranteed 6.5% beats a hoped-for 7% more often than you think.
The oldest question in personal finance, answered with fair math: both paths spend the same total dollars over your loan term. Paying extra kills the loan early and then invests the freed-up payment; investing puts the extra in the market from day one. This calculator runs both and shows the gap.
Borrowers with extra monthly cash use it to settle the pay-down-or-invest debate with fair same-outlay math instead of vibes. It makes the guaranteed-versus-expected tradeoff visible, which is the part most advice glosses over.
Yes — every extra dollar of principal you kill stops accruing interest at the loan rate, permanently, with zero volatility and (for student loans) no tax on the benefit. A 6.5% loan payoff is a guaranteed 6.5% return. The stock market's 7% average arrives with years of −20% mixed in, which is why the guaranteed side wins ties.
Grab the full match first, always — it is an instant 100% return, and neither loan payoff nor unmatched investing comes close. After the match, this calculator's comparison is the right frame: loan rate versus expected market return.
No — if you are on an income-driven plan heading toward forgiveness, extra payments can actually cost you money (you pay down a balance that would have been forgiven). Model that path with the student loan IDR calculator first, then use this one only if aggressive payoff is your real alternative.