Dear guRus How can I round of time in R to the nearest 30th minute please? For example suppose if >Sys.time() [1] "2014-11-21 22:49:05.59042 GMT" then I would like a function that outputs 22:30:00. if Sys.time is 12:13:22 then I would like to get 12:00:00 etc. Any help would be appreciated. Many thanks and regards, Raghu