Last reviewed 2026-09-02

Contact

One address handles everything: corrections, questions about the method, press, privacy requests and anything else.

Postal address: [Postal address to be added]

Reporting a calculation problem

The calculator keeps every input in the page URL, so the fastest way to report a wrong number is to copy that URL out of the address bar and paste it into the email. It carries the balances, APRs, fee, intro period and payment exactly as they were entered, which means the exact result can be reproduced without any back and forth.

Along with the URL, these help:

The figure on screen that looks wrong, and the figure expected instead.
Where the expected figure came from, if it came from somewhere: an issuer statement, a cardmember agreement, another calculator.
The device and browser, if the problem is that something did not display or would not accept an input.

Confirmed errors in the arithmetic get fixed in the calculation engine, covered by a test so the same mistake cannot return, and noted with a date on the page that carried it. Disagreements about an assumption rather than an error are just as welcome, and often end up as a new line on the methodology page.

Response expectations

Email is read within a few working days. Reports of a wrong number are answered first. Requests to exchange links, publish a guest post, or add a card offer are not answered, because the site does not do any of those.

What cannot be answered

Individual financial advice is outside what this site does. Questions of the form "should I transfer my balance", "which card should I apply for", or "is this offer a good deal for me" cannot be answered, whatever detail comes with them. This site publishes arithmetic and its sources, not recommendations, and no one here knows enough about any individual's circumstances to advise them. Anyone who wants personal guidance can look for a nonprofit credit counselling agency or a licensed financial professional. The terms of use set out the same limit in full.