Fidamen

Credit Card Payoff Calculator

This tool helps you estimate how long it will take to pay off a single credit card balance and how much interest you will pay under several common approaches: a fixed monthly payment, targeting a fixed term, or an approximate projection using minimum payments.

Results are numerical estimates intended to assist planning. They rely on standard amortization mathematics and simplifying assumptions; actual card statements, minimum payment rules, billing cycles, and interest compounding policies can change results.

Updated Nov 15, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record fde8fa0b205e • Reviewed by Fidamen Standards Committee

Estimate how long it will take to pay off the balance if you make a constant monthly payment (includes optional extra payment).

Inputs

Results

Updates as you type

Months to payoff

—

Estimated total interest

—

Final (last) payment amount (approx)

—

OutputValueUnit
Months to payoff—months
Estimated total interest——
Final (last) payment amount (approx)——
Primary result—

Visualization

Methodology

Calculations use standard amortization formulas: convert APR to a monthly rate and apply closed‑form algebra to estimate number of payments or required payment for a specified term.

When projecting minimum‑payment behavior, the tool uses an initial minimum payment as an approximation. Real minimum payments typically change as the balance drops; therefore minimum‑payment mode gives an approximate, conservative indication rather than an exact schedule.

For development, we follow engineering and data‑integrity best practices (NIST guidance on calculation integrity), standards awareness from ISO, and testing approaches consistent with IEEE software testing recommendations. Operational safety and user warnings follow general workplace safety communication principles referenced by OSHA.

F.A.Q.

How accurate are these estimates?

Estimates use standard amortization formulas and are accurate under the calculator's assumptions (fixed payment amount, fixed APR, monthly compounding). Accuracy decreases when minimum payment rules, fees, late charges, promotional rates, or variable APRs apply. See methodology for limitations.

What should I enter for APR?

Enter the annual percentage rate shown on your card statement. If you have a promotional or tiered rate, run separate scenarios for each APR to see the range of outcomes.

Why does the minimum‑payment method say 'approximate'?

Minimum payments typically change as the balance declines (often a percent of balance or a floor amount). This tool approximates payoff by treating the first computed minimum as a constant; that gives a conservative, easy‑to‑compare result but is not an exact amortization under real minimum‑payment rules.

What happens if my planned payment is less than the monthly interest?

If the monthly payment is less than or equal to the monthly interest on the balance, principal will not decline and payoff will not occur. The calculator will return an invalid or infinite payoff period in that case; increase the payment to cover interest plus some principal.

Can I rely solely on this tool for legal or financial decisions?

No. This calculator is for planning and educational purposes only. Verify numbers with your card issuer, a certified financial advisor, or official account statements before making binding decisions.

Sources & citations

Further resources

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: fde8fa0b205e

What changed (latest)

v1.0.0 • 2025-11-15 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

UI

v1.0.0

Governance

Last updated: Nov 15, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

  • MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
  • MINOR: New features or fields that do not change existing outputs for the same inputs.
  • PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

  • Verify formulas and unit definitions against primary standards or datasets.
  • Run golden-case regression suite and edge-case suite.
  • Record reviewer sign-off with credentials and scope.
  • Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

  • Uses exact unit definitions from the Fidamen conversion library.
  • Internal calculations use double precision; display rounding follows the unit's configured decimal places.
  • Not a substitute for calibrated instruments in regulated contexts.
  • Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-15 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: f36241fb18d9