100% Client-Side. Zero Server. Absolute Privacy.
UnitMaster Pro is a powerful, offline-first unit conversion tool designed for engineers, scientists, students, and professionals. Convert between hundreds of units across 12+ categories—all without an internet connection.
Try the demo instantly—no signup, no installation:
⚠️ Demo limited to 5 categories (Length, Mass, Time, Temperature, Pressure). Upgrade for full access.
| Feature | UnitMaster Pro | Online Converters |
|---|---|---|
| Data Privacy | ✅ 100% Offline | ❌ Data Sent to Server |
| Subscription Fees | ✅ One-Time Purchase | ❌ Ads or Premium Plans |
| Unit Categories | ✅ 12+ (Pro) | |
| History & Favorites | ✅ Included | ❌ Rarely Available |
| SI Prefix Support | ✅ Full (nano to tera) | |
| Currency Rates | ✅ Manual + API | ❌ Often Outdated |
| Internet Required | ✅ No | ❌ Yes |
- 📐 12+ Unit Categories: Length, Mass, Time, Temperature, Pressure, Energy, Power, Speed, Volume, Area, Angle, Digital Data, Currency
- 🔢 Full SI Prefix Support: Nano (n), Micro (μ), Milli (m), Kilo (k), Mega (M), Giga (G), Tera (T)
- 🌡️ Special Conversions: Temperature (Celsius, Fahrenheit, Kelvin), Currency (with live API)
- ⭐ Favorites: Save frequently used conversions
- 📜 History: Track all past conversions with timestamps
- 🔍 Smart Search: Find any unit by name, symbol, or category
- 🎨 Dark/Light Theme: Full theme support with toggle
- ⚙️ Customizable Precision: Adjustable decimal places and number formats
- 💾 Backup & Restore: Export/import all data as JSON
- 🔒 100% Offline: All data stored in IndexedDB—never leaves your browser
- Tailwind CSS — Styling
- Vanilla JavaScript — No frameworks
- IndexedDB — Client-side storage
- ExchangeRate-API — Optional live currency rates
git clone https://github.com/worldmohammad/unitmaster-pro.git
cd unitmaster-pro