About OneCalc
One platform for every calculator and converter — engineering, science, finance, solar and daily life.
What we build
OneCalc brings hundreds of converters and professional calculators into a single, fast, privacy-first workspace. From SI unit conversion to IEC-compliant solar design, everything runs instantly in your browser.
We believe professional tools should be free, accurate and available without sign-ups, watermarks or usage limits.
Privacy by design
File conversions, OCR and media processing run entirely client-side with WebAssembly. Your documents, photos and videos never leave your device.
Engineering accuracy
Unit conversions use exact SI base factors in full double precision. Solar and engineering calculators follow IEC and IS standards and always show the equation, working, assumptions and warnings.
What's next
We are expanding into financial, scientific, civil and AI-assisted calculators. Recent additions include a 22-tool financial suite (EMI, SIP, compound interest, loan amortisation), civil engineering tools for concrete, steel and cable sizing, and a 36-calculator solar design suite.
Every new tool ships with its governing equation, step-by-step working, SI units, engineering notes and a downloadable PDF report — so results can be checked, cited and shared, not just read.