In fact Julian dates do have day/month/year and were used up until the 16th century in much of Europe (until the 18th century in the UK and US and until the 20th in Russia and other places). The interval in days since 4713BC is used by astronomers and is usually called the Julian day. What the questioner really wants is the Gregorian date (i.e. what most people have been using since 1900).
The distinction is only really important for historians, for example worrying about the fact that Russia's "October Revolution" took place in what most of the world thought of as November.
As other posters have stated there are many CPAN modules for converting from Julian dates (or days) to and from Gregorian, Islamic, Jewish and all sorts of other dates (even Excel ones).