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?
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.