About Calvix

Calvix is a small, independent set of calculators built around one idea: a number on its own is not much use. If a calculator tells you your monthly payment is $500.95 but not where that figure comes from, you cannot check it, cannot adapt it, and cannot tell whether it applies to your situation at all.

So every calculator here publishes the formula it uses, works through a real example with real numbers, and says plainly where the model stops being appropriate.

How the calculations are checked

Each formula is written as a standalone function and covered by automated tests that run before anything is published. Those tests check the ordinary case, but they spend more effort on the awkward ones — zero interest rates, fractional terms, negative or empty inputs — because those are where calculators quietly produce nonsense.

The worked example in each article is generated from the same code that powers the calculator, so the article and the tool can never drift apart.

What these calculators are not

They are estimates for general information. They are not financial, medical, tax or legal advice, and they cannot know the specifics of your situation. Lenders round differently, clinical guidance varies between countries, and tax rules change. Treat the output as a well-explained starting point for a conversation with someone qualified, not as a final answer.

Privacy

Calculations run entirely in your browser. The numbers you type are never sent to a server, never stored, and never leave your device. See the privacy policy for the full detail, including what third-party advertising does collect.

Corrections

If a result looks wrong, it might be. Please get in touch — a reproducible example with the inputs you used is the fastest way to get it fixed.