About ExaCalc
Our mission and what powers the platform.
ExaCalc started as a weekend project to replace the dozens of ad-ridden calculator sites we kept landing on when we needed to convert a unit, plan a mortgage, or check a BMI. Today it is a hub of more than 100 calculators, converters, and financial tools spanning finance, science, engineering, health, and everyday utilities.
Every tool runs client-side, so your numbers never leave your browser and results stay instant and private. The site is a Progressive Web App, which means after your first visit it works offline and can be installed like a native app.
What we care about
Fast and free
Every tool loads in under a second. It keeps working offline after your first visit. Free forever, with no paywalls on core functionality.
Privacy first
Calculations run entirely in your browser, your inputs never touch a server, and the cookieless analytics we use spot trends without tracking anyone individually.
Global reach
Currently available in English, with more languages on the roadmap.
Accuracy matters
Each formula is checked against trusted references before it ships. When an answer depends on assumptions, like compounding frequency or tax jurisdiction, we spell them out instead of burying them in fine print.
How it works
ExaCalc is built on a modern, boring stack: Next.js 15, React 19, TypeScript, and Tailwind CSS. The math happens entirely in the browser using plain JavaScript, with no WebAssembly and no backend round-trip. Pages are pre-rendered at build time and served from the edge, so even users on slow mobile connections see results in under a second.
We use a pattern-matching natural-language search that works without any AI keys or server calls. Ask "15% of 200" or "convert 5'10" to cm" and you'll land on the right tool with the inputs pre-filled.
Who we are
ExaCalc is a small indie project, built and maintained by a tiny team with a genuine frustration: every time we needed to quickly check a mortgage payment, convert a unit, or estimate a calorie deficit, we ended up on sites that were slow, bloated with ads, locked behind paywalls, or simply inaccurate.
So we built what we wanted to use. No venture capital. No corporate structure. No data sold to advertisers. Just a focused effort to give everyone, from students and engineers to accountants, parents, doctors, and developers, the calculation tools they actually need, fast and free.
We fund the project through unobtrusive ads on the free tier and optional Pro features for users who need step-by-step solutions, higher API limits, or white-label embeds. If you want to say hello, report a bug, or suggest a tool, we genuinely read every email at kingedwardblue@gmail.com.