About OnlineToolKit

OnlineToolKit is a collection of free, browser-based utility tools for developers, students, freelancers and anyone who needs a quick calculation or conversion.

Why these tools exist

Most online tools are either buried behind ads, require signup, or upload your data to a server you don't control. Every tool on this site runs entirely inside your browser. Your text, numbers and files never leave your device.

How the site stays free

This site is supported by advertising and affiliate links. Ads are clearly labelled and never interfere with the core function of a tool. We do not sell, rent or share any personal data — partly because we never collect it in the first place.

Who it's for

• Developers — JWT decoding, hash generation, UUIDs, regex testing, subnet and chmod calculators, JSON to CSV
• Students — GPA, percentage, BMI, age and date calculators
• Freelancers and small business — margin, VAT, ROI and discount calculators
• Everyone — password generator, unit and colour converters, stopwatch, Morse code

Accuracy

All calculations use standard, published formulas and are unit-tested before release. Financial calculators are estimates for planning purposes and are not financial advice. Health calculators are estimates and not a substitute for professional medical guidance.

Feedback

Found a bug or want a tool added? Use the contact page — requests genuinely shape what gets built next.