About OpenCalcy

OpenCalcy is a free collection of 200+ online calculators — loans, investing, India finance, body & fitness, pregnancy, math, DIY, science, and developer tools. Built with plain PHP and modern front-end UX — fast, private (favorites & history stay in your browser), and SEO-friendly.

Extras beyond the basics

• Shareable URLs that restore your inputs
• Local favorites and recent history
• Dark mode and keyboard-friendly forms
• Formula notes and related tools on every page

Calculations are for educational / planning use. Verify critical financial or medical decisions with a qualified professional.