Kastavo

About Kastavo

Kastavo is an international portal of free online tools — converters, calculators, generators and validators that run directly in your browser, with no installation and no sign-up.

Why trust Kastavo?

FreeEvery tool is, and will remain, free, with no hidden limits.
No installationNothing to download or install — everything runs right in your browser.
No required sign-upUse any tool immediately, with no account and no login.
Works on desktop and mobileA responsive interface, built to work well on any screen size.
Built for performanceLightweight, fast tools, with nothing getting in the way of the experience.
Content kept up to dateExplanations and examples reviewed continuously alongside each tool.

What Kastavo is

Kastavo brings together simple everyday tools — like unit converters, calculators and generators — in one place, with a fast, consistent experience across all of them.

Each tool is built to solve one specific task in a few seconds, without invasive ads, unnecessary steps, or requiring you to create an account.

Our mission

Our mission is to build the most useful, trustworthy and accessible tools portal on the internet, and to do it sustainably over many years — not just shipping isolated tools, but building a coherent ecosystem of utilities and content.

We believe Kastavo's growth should be a consequence of the quality of what we offer, not the other way around.

Tools that run right in your browser

The vast majority of Kastavo's tools run entirely in your browser. That means instant results, no waiting on a server, and — in most cases — the values you type never need to leave your computer or phone.

That's an intentional design principle: speed and privacy aren't an afterthought, they're part of how Kastavo is built.

Always evolving

Kastavo is just getting started. New tools, categories and content are added continuously, aiming to cover more and more everyday tasks — from technical conversions to utilities for developers, text, images and beyond.

Available in multiple languages

Kastavo was built to be multilingual from day one. The site is currently available in Portuguese, English and Spanish, with units, number formats and content adapted to each language — and more languages may be added as the project grows.