HistoryCal is a practical calculator designed to work with historical dates and calendars.
The calculator will allow you to work with many different world calendar schemes and calculate ranges and ages based on these calendars. The calculator also has a script language that allows you to create variations of the built-in calendars: calendars that shift the new year to a different day; hybrid calendars that switch between schemes; local observational calendars that depend on a particular location; year counts that change for specific eras (regnal calendars) and calendars that require adjustment due to subtle differences in calculation.
