Unit conversion errors have consequences. NASA lost a $125 million Mars orbiter in 1999 because one engineering team used metric units and another used imperial — the spacecraft burned up in the Martian atmosphere. In everyday life, miscalculating medication doses (mg vs. mcg), cooking measurements (cups vs. ml), or tire pressure (PSI vs. bar) can range from mildly inconvenient to genuinely dangerous.
UnitWiz covers 10 categories with all common units and many less-common ones. Temperature conversion is handled exactly (Celsius, Fahrenheit, and Kelvin use precise formulas, not approximations). Data units include both decimal (SI: 1 kB = 1000 bytes) and binary (IEC: 1 KiB = 1024 bytes) standards — a distinction that matters when reading hard drive specs vs. operating system file sizes.