Zend Measure

Zend_Measure provides a generic and very easy way for working with measurements.
Using Zend_Measure, you can convert measurements into different units of the same type. They can be added, subtracted and compared against each other. From a given input made in the user's native language, the unit of measurement can be automatically extracted.
Of course a great number of completely different units of measurement is being supported. Most of these units are of a physical nature, but there are also special measurements used, in numerics or other areas, that are only partly physical - or not at all.
The following quickstart tutorial shows how units of measurement can be automatically converted.