Hi, I'm Tathagata Sarkar, a product designer in Mumbai. I've spent six years designing systems at scale, and I kept doing the same small sums by hand: pixels to rem, viewport maths, turning a CSS snippet into Tailwind classes or email-safe inline styles.

So I built the tools I wanted. They're fast, free and private: everything runs in your browser, and nothing you type or paste is uploaded or stored.

CSS Toolkit is a growing collection. Every new calculator will appear on the All tools page as soon as it's ready.

If a tool saved you some time, you can buy me a coffee. It keeps the tools free and the next ones coming.