Calculators

OnlineToolkit is a collection of free, fast browser utilities for text, developers, security, and everyday calculations. Open a tool, use it immediately, and leave when you are done.

No. The tools are available without signup. Your session stays in the browser for most utilities, so you can start working right away.

Most tools process input locally in your browser. We do not use your pasted text or files for training, and nothing is stored on our servers for typical client-side tools.

You need a network connection the first time you load a page. After that, many tools continue to work with cached assets until you refresh or clear site data.

Yes. OnlineToolkit is free to use. There are no paywalls for the utilities listed in the catalog.

Browse by category from the Categories page, open the full Tools directory, or use the search on the homepage and tools page to filter by name or description.

Use a current version of Chrome, Firefox, Safari, or Edge. Tools rely on modern JavaScript; very old browsers may not work correctly.

Yes. Copy the output from any tool and paste it into another—for example, format JSON, then convert or diff it in a follow-up step.

We ship improvements and new utilities regularly. Each tool page reflects the latest behavior when you load the site.

OnlineToolkit is built for interactive use in the browser. There is no public HTTP API; integrate by linking to the tools you need.

Check that your input matches the expected format—for example valid JSON for a formatter. Error messages usually point to the line or rule that failed.

Use your project’s issue tracker or contact channel if you are self-hosting. For the public site, check the repository or support link in the site footer if provided.