Debt Payoff: Checking Whether a Debt Payment Reduces Principal
A payment must cover the modeled interest before it reduces the balance. Compare your chosen payment with the first month of interest, then look at the payoff schedule rather than dividing the balance by the payment alone.
Use the Debt Payoff Calculator to enter your own figures and compare the result with the worked example below.
Debt Payoff formula
Interest each month = opening balance × annual rate / 12. Each payment first covers interest. The remainder reduces principal. We repeat until the balance reaches zero, adjusting the last payment.
Worked example
A $1,200 balance with no interest and payments of $100 is repaid in 12 months.
These are illustrative inputs, not current prices, rates or recommended targets. Where a currency is shown, keep all comparable money amounts in the same currency; conversion examples identify the two sides separately.
How to interpret the result
New borrowing, variable rates and missed payments can change the schedule. Update the balance when these occur.
Related calculations
Method and further reading
The example follows the FinMathly calculator method. For broader background, see CFPB: Building a budget. The background resource may use jurisdiction-specific terms; it does not replace the assumptions of this calculator.
Featured photograph: Pexels.