How Xerobit Tools Are Built and Tested

Last updated: 2026-10-29

Xerobit is a collection of free calculators, converters, generators and developer utilities. This page explains how each one is built and what we do to keep the answers correct, so you know how far to trust a result and how to tell us when we get one wrong.

Everything runs in your browser

Calculations happen in your browser with JavaScript. The numbers, text and files you enter are never sent to our servers, so a password length, a loan amount or a private JSON file stays on your device. Our privacy policy covers the few things that are collected, such as anonymous page-view analytics and cookie choices.

Exact constants and stated formulas

Unit converters use the defined value of each unit, for example one inch is exactly 2.54 centimeters, one pound is exactly 0.45359237 kilograms and one US gallon is exactly 3.785411784 liters. Calculators show the formula they used next to the result, so you can check it by hand or repeat it in a spreadsheet. Results are rounded only for display.

How we check the results

• Every tool ships with test cases computed independently of the code, including edge cases such as zero, negative numbers, empty input and very large values. The tests run on every change and a failing tool does not go live.
• Worked examples on a page are produced by the same code the tool runs, so the examples and the tool cannot disagree.
• Calculators that return a number are cross-checked against a second, independent calculation before publication, and disagreements are resolved against a published reference.
• Pages are tested in the browser for accessibility, mobile layout and speed.

What the written guidance is for

Each tool page explains how the answer is worked out, shows a reference table of common values, lists typical uses and common mistakes, and answers the questions people ask most. We keep claims to widely documented facts, and we leave a feature out when we cannot verify it.

Estimates, not advice

Health, fitness, finance, construction and engineering calculators give estimates based on standard published formulas. Real situations depend on details a general formula cannot know. They are not medical, financial, engineering or legal advice, so check important results with a qualified professional.

Corrections

If a result looks wrong, tell us through the contact page with the input you used and the answer you expected. We reproduce the problem, fix it, and update the page and its tests. Pages show the date they were last changed.

Independence

Xerobit is free to use. Where advertising appears it is clearly separate from tool results, and it does not change how any tool calculates or what we recommend.