Comprehensive Unit Converter

Why "convert" is really "multiply by a ratio of 1"

Any unit conversion works by multiplying by a conversion factor that equals 1 — like 12 inches per 1 foot. The value doesn't change, only the units describing it, which is why chaining several conversions together still gives an exact answer.

The rounding trap in multi-step conversions

Rounding an intermediate result before finishing a multi-step conversion — miles to feet to inches, for instance — can introduce small errors that compound. Where precision matters, convert directly with a single combined factor rather than rounding at each step.