Dear List, given a vecor of times in 5,15 and 30 minutes and a start point in time, lets say 09:30:00, how do I add up those times to the start time getting a cumulative time sequence? mt<-times(c('00:05:00', '00:15:00', '00:30:00')) mt wanted 00:05:00 09:35:00 00:15:00 09:50:00 00:30:00 10:20:00 Regards, René