Ideally designed to help the pilot fill in his log book, Hour Calculator can more generally be used to quickly add or substract hours and minutes based figures of any kind. Hour Calculator allows the calculation of time difference, the spent time coming from an hourmeter, make a log book sum-up, find an ETA, a.s.o... Hour Calculator allows a straight forward digits entry, without a ":" separator. Hour Calculator provides as well an history of the entries and calculations for verification purpose