# Debt Payoff Calculator

> Debt payoff calculator: see how long a loan or credit card takes to clear and how extra monthly payments cut interest and shorten the payoff date. Free.

- **Canonical URL:** https://boringtoolskit.com/debt-payoff/
- **Category:** Finance & Investing
- **Evidence level:** authored-methodology
- **Reviewed:** July 26, 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

Each month interest = balance x APR/12; payment first covers interest, remainder reduces principal; the tool compares your payment plus extra against the base payment.

## Worked example

A $15,000 balance at 19.9% APR: paying $500 a month (including $100 extra) pays off in 3 years 6 months with $5,920.65 interest, 1 year 6 months sooner than the $400 base payment (5 years).

## Assumptions

- This page models one debt only. It is not a full avalanche/snowball planner.
- APR, payment, fees, and new purchases are held constant.
- If payment does not exceed monthly interest, the balance may never amortize.

## Common questions

### Is this a full avalanche calculator?

No. A true avalanche/snowball calculator needs multiple debts. This tool is a single-debt payoff estimator.

### What should I compare?

Compare base payment versus extra payment and review total interest saved.

### Does it include new purchases or late fees?

No. Add those separately or treat this as a planning-only estimate.

## Related tools

- /credit-card-payoff-calculator/
- /balance-transfer-savings-calculator/
- /emergency-fund-calculator/

## Sources

- [Credit card resources](https://www.consumerfinance.gov/consumer-tools/credit-cards/)
- [Calculation methodology](/methodology/)

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*Local planning estimate. Verify current terms, rates, and policies before acting.*