ConvertVecta

170 categories and 3,651 units. Calculations stay on-device; connects only to check signed paid-license revocations.

ConvertVecta is a unit converter that shows its work. Every result carries a precision label and the exact definitions it used - not an unexplained number. Convert across 170 categories and 3,651 units: length, mass, temperature, area, volume, pressure, energy, power, angles, data units, currency (dated reference rates), colors, number bases, a DST-correct world clock across 52 cities, and 11 calendars. Ask in plain words - "5 ft 3 in to cm", "350 F to C", "how many ml in 2 cups". Honest by construction: it refuses to fabricate. It won't turn metres into kilograms, won't guess a cooking conversion without a density, and labels currency as a frozen reference rate, never a live feed. Private by default: the whole engine runs locally as WebAssembly. Conversions never use the network and your inputs never leave your browser. The only background request is a public signed revocation-list check when a paid license is stored; it sends no calculator input, cookies, account data, or request body. Free forever: every conversion, category, calendar and the world clock. A one-time ConvertVecta Pro upgrade adds the interactive explore instruments (a fillable glass, a dual-scale ruler, dials, gauges, and multi-unit compare boards). No subscription, no account. Available in 25 languages with full right-to-left support.