Debt Opportunity Cost Calculator
How Much Is My
Debt Really Costing Me?
Your debt doesn't just cost you interest — it costs you every dollar of investment growth that money could have earned. See the number that actually hurts.
Add up all credit cards, auto, student loans, etc.
The S&P 500 has averaged ~10% gross / ~8% after inflation since 1957. Past returns don't guarantee future results.
Add total debt balance & APR to calculate true cost (optional)
Enter your monthly debt payments above to see your opportunity cost.
Example: $650/mo in debt payments invested for 30 years at 8% = $975,000+
Why opportunity cost is the real cost of debt
Most people think about debt in terms of interest. If you owe $25,000 at 22% APR, you'll pay thousands in interest charges before you're free. That's painful — but it's only half the story.
The other half is opportunity cost: what that money could have become if it were invested instead of going toward debt payments. Every month you send $650 to a creditor is a month that $650 isn't compounding in your favor.
Over 30 years at an 8% annual return — the S&P 500's historical average — a single month of $650 payments becomes roughly $2,100. Every twelve months of payments eventually turn into real wealth, if given the chance.
How this calculator works
The calculator uses the future value of an annuity formula — the standard compound interest calculation for regular monthly investments:
Where PMT is your monthly payment,
r is your monthly return rate (annual rate ÷ 12),
and n is the number of months invested.
After your debt payoff date, we project what those same payments would grow to over 10, 20, and 30 years of investing. The "get debt-free sooner" section shows the compounding advantage of starting earlier — even a year or two makes a dramatic difference thanks to compound interest.
The compound interest gap
Compound interest has often been called the eighth wonder of the world — and it works both for and against you. When you carry high-interest debt, compound interest works against you, growing your balance faster than your payments can shrink it.
When you invest, compound interest works for you. Each year's gains become the foundation for the next year's gains. A 10-year head start on investing doesn't just add 10 more years of contributions — it adds 10 more years of exponential growth on everything that came before.
This is why getting debt-free faster isn't just about saving interest. It's about capturing more years on the investing side of the equation, where compounding works in your favor instead of against you.
How to actually get debt-free faster
There are two main debt payoff strategies:
- › Avalanche method — pay minimums on all debts, then put every extra dollar toward the highest-APR debt. This minimizes total interest paid and is mathematically optimal.
- › Snowball method — pay minimums everywhere, then attack the smallest balance first. Quick wins build momentum and motivation — research shows this approach improves follow-through.
Toya AI takes a third approach: analyzing your real account data and optimizing across all debts simultaneously, adapting as your situation changes. Our users typically see their debt-free date move 18–24 months closer when they switch to an optimized plan.
Frequently asked questions
Why does the calculator use 8% as the default return?
The S&P 500 has returned approximately 10% annually on a nominal basis since 1957, and around 7–8% after adjusting for inflation. We default to 8% as a conservative real-return estimate. You can enter any rate — financial advisors often use 6–7% for planning purposes to build in additional conservatism.
Does this include investment taxes?
No — for simplicity, this calculator shows pre-tax growth. In tax-advantaged accounts like a 401(k) or IRA, your investments grow tax-deferred or tax-free, so the numbers shown can be accurate for retirement savings. In taxable accounts, subtract your capital gains tax rate from the projected return. This doesn't change the fundamental insight: debt has a massive hidden opportunity cost.
What if I can't invest the full payment amount?
That's a realistic scenario — freed-up debt payments often go partly toward higher living standards and partly toward savings. Even investing half your payment produces dramatic results over 30 years. The full-payment scenario shown here represents the maximum potential, helping you see what's possible if you direct those freed dollars intentionally.
How does Toya help me get debt-free faster?
Toya connects to your real accounts and builds a personalized payoff plan that optimizes payment allocation across all your debts using AI. It tracks progress automatically, adapts when your situation changes, and monitors your credit score. Most users find a path to payoff significantly earlier than their current trajectory.
Stop paying the opportunity cost of debt
The sooner you're debt-free, the sooner compound interest starts working for you. Toya builds the fastest path out.
Get my Toya plan