About

StreamerOS Math Calculators is a small set of free calculators for everyday number questions: percentages and percent change, age, days between dates, adding to a date, hours worked, ratios and averages, with short guides that explain the formulas.

It is built and maintained by Yaseen Khatib, a full-stack AI engineer, as part of the StreamerOS project. Many calculators give an answer without showing how it was reached, so every page here states its formula and works a few examples you can check by hand.

How the calculators work

Every calculator runs in your browser using standard JavaScript. The numbers and dates you enter, including dates of birth, are processed on your device and are not sent to a server or stored. The site is a static website hosted on GitHub Pages.

What the results are, and are not

The calculators do exact arithmetic on what you type, and the date logic is tested against known cases. They are general tools, not financial, legal or medical advice. For legal ages and deadlines, check the rules that apply in your country; for example, the date a 29 February birthday is observed differs between countries.

How the site is funded

The calculators are free. The site may show Google AdSense ads to cover hosting and development time. Ads never change the result of a calculator.

Corrections

If a result is wrong or a guide contains a mistake, please use the contact page. Fixes are made in the open and the guides are updated.