Tempo pagar dívida
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The 'Time to Pay Debt' calculator estimates the period required to settle a long-term debt with fixed monthly payments. It uses the logarithmic formula log(1 + rP) / log(1 + r), where 'r' is the monthly interest rate and 'P' is the monthly payment. This helps understand how long it will take to clear debts such as personal loans or mortgages.
Use this tool when comparing different payment scenarios, such as adjusting monthly amounts to shorten the term or evaluating the impact of variable interest rates. It's especially useful for planning debt repayment and avoiding interest cost accumulation over time.
Caveats: The formula assumes fixed interest rates and constant payments. If the debt has variable rates or penalties, the result will only be an approximation. Additionally, it does not account for inflation or other associated debt costs.
Frequently asked questions
How does the logarithmic formula calculate payment time?
It compares the growth of the monthly payment (rP) with the interest rate (r) to determine how many installments are needed to reduce the debt to zero.
Does this calculator work for all types of debt?
It works best for debts with fixed rates and constant installments, such as loans with predefined payment schedules.
What happens if I increase the monthly payment?
Increasing the payment amount shortens the total term by directing more value towards amortizing the debt principal.
What if the debt has variable rates?
The result will be an estimate, as the formula does not account for interest rate changes over time.