The aforementioned tags serve the same purpose across nearly all the languages and their wiki-excerpt mentions the following as well:

Date-difference will give difference in the number of days, months, years etc. between any two calendar dates. (synonyms in stackoverflow.com: datediff, date-diff, date-difference)

I'd request community to either burninate two of the tags (not voting for it) or synonimize the less used (13 questions) and (76 questions) and map it to widely used (318 questions).