Inputs

Loaded your last inputs

Current balance ($)

APR (annual interest %)

Monthly payment type

Monthly payment ($)

Extra payment each month ($)

One-time extra payment (applied upfront) ($)

Uses standard amortization math. Estimates only.

Results

Base payoff time

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New payoff time

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Interest saved

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Time saved

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Scenario loaded from shared link.

How this model works (assumptions) +

Interest accrues monthly using APR ÷ 12.
Payments are applied once per month (modeled as end-of-month timing).
Fixed payment: your monthly payment stays constant (like a loan).
Credit card minimum: minimum payment recalculates monthly as “% of current balance” with an optional floor.
The “base” scenario uses your payment/minimum with no extra monthly or one-time extra payment.
The “with extra” scenario adds your extra monthly payment every month, plus a one-time extra payment applied upfront.
Extra payments are assumed to go toward principal after interest is paid for the month.
No fees, penalty APR changes, promo rates, payment timing quirks, or issuer-specific minimum rules beyond what you enter.
If your payment is less than monthly interest, the balance may not decline (negative amortization).