Real Cost of Debt Calculator
See the true cost of carrying debt — including lost investment opportunity. Every dollar in debt payments is a dollar not invested.
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The Double Penalty of Debt
Debt has a cost most people never calculate: the opportunity cost. Every dollar spent on debt payments is a dollar that cannot be invested. This creates a double penalty: you pay interest TO the lender AND you miss investment returns FROM the market. On $25,000 at 18% APR with $500/month payments: you pay $9,800 in interest over 67 months. But if that $500/month were invested at 8% instead, it would grow to $39,000 — meaning the $25,000 debt actually cost you $14,800 ($9,800 interest + $5,000 missed growth).
This is why paying off high-interest debt is considered the best "investment" you can make. Paying off 18% debt is equivalent to earning an 18% guaranteed return — something no stock market can reliably offer. Only after eliminating high-interest debt should you focus on investing. The exception: always contribute enough to your 401K to get the full employer match (that is a 50-100% guaranteed return that beats any debt payoff). Use our Snowball vs Avalanche Calculator to optimize your payoff strategy.
Debt vs Investing: The Priority Framework
Financial advisors generally recommend this order: (1) 401K to employer match — free money, always do this first. (2) Pay off debt above 10% interest — guaranteed high return. (3) Build emergency fund (3-6 months) — prevents new debt. (4) Pay off debt between 5-10% — better than bond returns. (5) Max tax-advantaged investing (Roth IRA, HSA, 401K). (6) Pay off debt below 5% (mortgage) — the math says invest, but being debt-free has psychological value. Calculate your emergency fund with our Emergency Fund Calculator and check your retirement pace with our Retirement by Age Calculator.