About Us

CalcMyCard is a free set of credit card calculators and plain-English guides. It exists to help you estimate what a credit card balance is costing you and how to pay it off faster — with no login, no sign-up form, and no card offers.

Who runs CalcMyCard

CalcMyCard is built, written, and maintained by Ali Ahmad, the site’s founder. Ali builds and tests the calculators, writes and updates the guides, and handles corrections. You can find him on LinkedIn.

Ali is the only person who works on the site. There is no separate editorial board or panel of outside reviewers, and CalcMyCard doesn’t claim review by a licensed financial professional. What we do instead is make every calculation checkable: the formulas are published on our Methodology page, the calculators are tested automatically (see below), and the rules and rates in our guides link to their primary sources.

What we’re not

CalcMyCard is not a credit card issuer, lender, credit union, or financial adviser. We don’t sell or recommend specific cards, and we don’t accept payment from card issuers or lenders to influence any result or article. Everything here is general, educational information, not personalized financial advice. For decisions about your own situation, consider a qualified financial adviser or a nonprofit credit counselor.

How the calculators work

Our calculators use clearly disclosed simplified models for planning. Most payoff and interest calculators use APR ÷ 12, while our Daily Periodic Rate Calculator provides a daily-rate view using APR ÷ 365 or 360 and an average daily balance. Many card issuers charge interest with a daily periodic rate on your average daily balance, and results can also differ because of transaction timing, fees, new purchases, grace-period rules, promotional terms, and other card-specific terms — so treat our results as estimates, and check your statement or cardholder agreement for your card’s actual terms. The full formulas for every tool are on the Methodology page.

All calculations run in your browser. The numbers you type are not sent to our server, stored, or shared.

How the calculators are tested

All 16 calculators are tested by an automated test suite that loads the live calculator code in a real browser, types in inputs, and compares what the page shows against two things: hand-worked examples (for instance, $5,000 at 24% APR with a $150 payment should show $100 of interest and $50 of principal in the first month, then $99 of interest the next month) and a separate reference implementation of the same formulas.

The suite has 157 test cases covering all 16 calculators, including edge cases: a $0 balance, 0% and 100% APR, decimal APRs, payments equal to or below the monthly interest, a $1 balance, minimum-payment floors, 0% promo and 0% fee transfers, equal APRs and equal balances in the snowball/avalanche tool, minimums larger than a card’s balance, and credit limits of $0 or utilization above 100%. It also fails if any result shows “NaN” or “Infinity”, or if the browser logs an error.

Last full test run: October 25, 2026 — all 157 cases passed. That run added checks for APRs over 100%, fractional promo months, balance transfer fees, the origination fee option in the consolidation calculator, key facts in our guides, link tap-target sizes and heading order. See what every test case checks. The October 16, 2026 run found and fixed these problems: a shared link to the Minimum Payment Calculator with an issuer preset (such as Discover) used the wrong formula; shared links to the multi-card and utilization calculators dropped or restored cards; several calculators accepted negative rates or amounts; payoffs longer than 50 years were described as payments too low; and the payoff and minimum payment charts could stop short of the final month. An earlier run on September 25, 2026 found and fixed these problems: the snowball/avalanche calculator didn’t roll a paid-off card’s minimum into the next card and could show a meaningless interest total when payments never cleared the debt; the 0% intro APR calculator could round the required payment down by a cent; the utilization calculator treated a $0 credit limit as $1; and the consolidation calculator accepted a 0-month promo period or loan term.

Sources

Statements about credit card rules and rates are checked against primary sources, and each page lists the ones it relies on. The main ones are:

• The Federal Reserve’s G.19 Consumer Credit release for average credit card interest rates.
• The Consumer Financial Protection Bureau’s credit card resources and Regulation Z (Truth in Lending) for rules such as grace periods, the 21-day statement rule, payment allocation, and limits on rate increases.
• myFICO and FICO for how credit utilization relates to credit scores.

Corrections

If you find a calculator result that looks wrong or a fact that’s out of date, please email contact@calcmycard.com with the page link and, for calculators, the exact numbers you entered. Confirmed errors are fixed, the page’s “Updated” date changes, and calculator fixes are added to the test suite so they can’t come back. Our Editorial Policy has the details.

Last methodology review

The calculation methods, the Methodology page, and the rules cited in our guides were last reviewed on September 25, 2026.

Contact

Questions, corrections, or ideas for a new calculator: contact@calcmycard.com, or see the Contact page.