Save vs Pay Off Debt Calculator
Amount, rates & horizon
Your result will appear here
Fill in the fields on the left and this updates as you type.
Know what this estimate is based on
- Jurisdiction
- United States card and lending practice
- 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 cardholder agreement for the figures that bind.
- Source links checked
- Jul 30, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
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
500,000 against 18% debt 'returns' 1,144,000 over five years versus 734,500 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.