A collection of handy browser-based calculator tools, live at laskurit.pomeranssi.fi.
All calculations run locally in the browser. No data is sent to any server, so you can safely calculate password hashes and other sensitive values.
- Time & dates — date arithmetic, timestamps, name days
- Numbers — binary, hexadecimal, octal conversions
- Identifiers — Finnish national ID (hetu) generation/validation, company IDs, bank references
- Colors — color conversions and analysis
- Byte sizes — byte/KB/MB/GB conversions
- Links — URL encoding/decoding and manipulation
- Data pipeline — chainable text/binary operations: encoding (Base64, hex, URL, JWT decode), text transforms (ROT-N, case, sort, trim, unique), formatting (JSON, XML, JSONPath extract and set), hashing (MD5, SHA-*, PBKDF2), compression (gzip, deflate), and display (hex dump, image/SVG preview, statistics). Supports text input, file drag-and-drop, and URL fetch. Operations are drag-and-drop reorderable with per-operation configuration.
- Cryptography — MD5, SHA-1, SHA-256, SHA-512 hashing
- Pixel density — DPI/PPI calculations
- Work time — track start and end times for a day, with lunch and commute deductions
- UUID — validation and UUID v7 timestamp parsing
- Finnish and English — the whole UI switches language, and every page has a path in both
- Dark mode — system, light, and dark theme support
yarn # Install dependencies
yarn start # Dev server at http://localhost:3000yarn build # Production build (output in dist/)
yarn test # Run tests
yarn lint # ESLint + TypeScript type checking
yarn fix # Auto-fix ESLint issues
yarn deploy # Build and deploy to production- React 19 + TypeScript 6
- Tailwind CSS 4 + shadcn/ui components
- React Router 8
- Vite 8 (build & dev server)
- Vitest (testing)
- @dnd-kit (drag-and-drop)