Metric - the internationally acknowledged system of measurement based on a decimal division. It’s been introduced in 1799. Today the USA is the sole industrialised country that uses the imperial system instead of the metric system.
We use rounding at unit-conversion.info. This means that some results will be rounded to avoid the numbers getting too long. While often rounding works up to a specific decimal place, we’ve decided that limiting the length of the result to 13 digits would be more favorable to keep the results consistent. The converters accept scientific notation and converts immediately.