Adding “date completed” timestamp in org-mode

Question

In org-mode, I would like to add a timestamp to a TODO marking the date completed. What is the best way to do this?

Answer 1

You can set org-log-done to put the completion time in the CLOSED property. The possible values are (as strings):

nil Don't add anything, just change the keyword

time Add a time stamp to the task

note Prompt for a note and add it with template `org-log-note-headings'

It is also possible to log any state change by adding "!" or "@" to the keyword definition. For example,

TODO(t)" "NEXT(n)" "STARTED(s!)" "|" "DONE(d!/!)

will add a log entry whenever you change the state to STARTED or DONE, but not TODO or NEXT. Using "@" instead of "!" will prompt for note when entering that state.