Save vs Pay Off Debt Calculator
Amount, rates & horizon
Your result will appear here
Fill in the fields and this updates as you type.
Know what this estimate is based on
- Jurisdiction
- United States — Truth in Lending disclosure and the CARD Act set the floor; the terms that decide your balance are in your cardholder or loan agreement
- Rules and time period
- APRs, fees, promotional periods and minimum-payment formulas are the ones you enter; an issuer can change several of them with notice.
- Scope and limitations
- Educational estimate only. Your issuer sets the minimum-payment formula, how a payment is allocated across balances, when interest is charged and any fees or promotional terms — check your agreement for the figures that bind, and expect a payoff date to move if a payment is late.
- Source links checked
- Sep 19, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
Primary sources
How to use
- 01
Enter the amount available.
- 02
Set your debt rate and expected investment return.
- 03
Choose a horizon to see which wins.
Good to know
Guaranteed versus expected
Paying off debt is a guaranteed return equal to its rate; investing offers a higher but uncertain return. The right choice compares the two.
The formula
Compare amount × (1 + debt rate)^years against amount × (1 + investment return)^years; the higher debt rate usually wins on certainty.
A worked example
$10,000 against 18% debt 'returns' $22,878 over five years versus $14,693 invested at 8% — clearing the debt wins decisively.
Frequently asked questions
Should I pay debt or invest?
Paying debt is a guaranteed return equal to its rate; investing is higher but uncertain. Compare the two.
What's the simple rule?
If your debt rate exceeds your expected return, pay the debt; if it's much lower, investing often wins.
What about high-interest debt?
Clearing high-interest debt (like cards) almost always beats investing — it's a guaranteed double-digit return.
How does the calculator decide which option wins?
Both options start with the same amount and run for the same number of years. The debt side grows it at the debt rate — what the debt would become if you left it alone — and the investing side grows it at your expected return. Paying off the debt wins when its rate is at least the expected return, and the gap shown is the difference between the two end values. Because both sides compound for the same years, the length of the horizon only widens the gap; it never flips the verdict. Both rates are held constant, so a variable-rate debt is only as certain as the rate you enter.
Does it include taxes or deductible interest?
No. Both sides are pre-tax: gains are not taxed and no deduction is applied to the interest. Interest on some debts is deductible, which lowers its true cost, and gains in a taxable account are taxed, which lowers the return you keep. For a closer comparison, enter the after-tax cost of the debt and the after-tax return you expect.
What should come before either choice?
Most plans put a basic emergency cushion first, because money used to clear a debt cannot be spent again, and an employer retirement match first, because it is an immediate return no market has to provide. After that, this comparison decides where the next dollar goes. The Emergency Fund Calculator and the 401(k) Calculator size those first two steps.