Calendar Convert
Convert dates between Gregorian, Julian, and other historical calendar systems — essential for working with ancient birth data in astrological software.
This tool matters because many astrological programs handle historical dates differently — some require Julian input, some convert silently, and some get it wrong entirely. Before entering a historical birth date into any software, it's worth confirming which calendar system it expects.
Practical example: Hildegard von Bingen's commonly cited birth date is August 17, 1098 — but that's in Gregorian, a calendar that didn't exist until 1582. The Julian equivalent is August 11, 1098, a 6-day difference that can noticeably affect the chart. Writing to a software developer can tell you which system they use; this tool tells you what to input.
Additional calendar systems across time, space, and cultures are also included.