Precision and floating-point arithmetic
Unit conversion inherently involves floating-point arithmetic. For example, converting 1 inch to centimeters (1 * 2.54 = 2.54) is exact, but converting 1/3 meter to centimeters can produce 33.333333333333336 due to IEEE 754 double-precision. Our converter rounds results to a configurable number of significant figures (default 10) and displays trailing zeros only when they matter. For engineering work, set the precision to 15 decimal places; for everyday use, 4 decimal places is sufficient.
The tool handles edge cases: absolute zero in temperature conversions (0 K = -273.15°C), zero-length conversions (0 meters = 0 feet), and unit prefixes (milli-, centi-, kilo-, mega-, giga-, tera-). Temperature is especially tricky because Fahrenheit and Celsius use both scaling and offset — the conversion formula is T(°F) = T(°C) × 9/5 + 32, not a simple multiplication.
Unit systems and internationalization
Most countries use the metric system (SI units), but the US, Liberia, and Myanmar primarily use imperial units. Many technical fields mix systems: aerospace uses imperial (feet, nautical miles, knots), while scientific research uses metric. Our converter supports both systems and common cross-system conversions like mph to km/h, pounds to kilograms, and inches to centimeters.
Data storage conversions (bytes, kilobytes, megabytes) have two conventions: decimal (1 KB = 1000 bytes, used by hard drive manufacturers) and binary (1 KiB = 1024 bytes, used by operating systems). Our tool lets you choose which convention to use, preventing the classic "500 GB hard drive shows as 465 GB" confusion.