How do you convert ce dates to ad?

Answer 1

Theoretically they are the same, ie just change the CE to AD

However, everyone seem to say that 2000 CE was the start of the 3rd millennium CE and so held big celebrations at the start of that year. If this is so, then the second millennium CE started 1000 CE and the first started 0 CE. But 1 BC was followed by 1 AD - there was no 0 AD - as when Dionysius Exiguus devised the BC/AD system in the year we now call 531 AD zero had not been invented: it was not invented for about another 400 years, coming to Europe about 600 years after the AD/BC designation was devised. As such the 3rd millennium AD started in 2001 AD.

The alternative is that the start of the 3rd millennium CE "celebrations" were actually a year early (and that the politicians who decided this can't actually count or don't know history/the calendar...) and that CE dates are AD dates, just under another name to try to appease though who may be offended by the Latin term Anno Domini - Year of the Lord, where the Lord in question is the Christian faith's Jesus Christ.