HistoryCalcHistorical Date & Calendar Converters
A date in an old document depends on the calendar it was written in. These converters move dates between the Gregorian, Julian, Hebrew, Islamic Hijri, French Republican and Mayan Long Count calendars. They also find the weekday of any historical date, decode the Aztec Sun Stone, look up the Chinese zodiac sign for a birth year, work out how old someone was at a historical event, and compare Roman emperors' reigns. Each page explains the rules behind the conversion, including leap-year differences.
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All Dates & Calendars Calculators
Age at Historical Event Calculator
Calculate how old you or a historical figure would have been during any historical event.
Aztec Sun Stone Calendar Decoder
Decode the Aztec Sun Stone calendar meaning. Enter any date to find your Tonalpohualli day sign, Xiuhpohualli position, and Calendar Round. Free online tool.
Chinese Zodiac by Birth Year Calculator
Enter a birth year to instantly find your Chinese zodiac animal, element, and traits.
Day of the Week for Any Historical Date Calculator
Find the exact day of the week for any date in history, from ancient Rome to today.
French Republican Calendar Converter
Convert dates between the Gregorian calendar and the French Revolutionary calendar.
Generation Calculator by Birth Year
Enter a birth year to find your generation (Gen Z, Millennial, Boomer, etc.) with exact date ranges.
Hebrew Calendar Date Converter
Convert Gregorian dates to the Hebrew calendar and back, including holidays and month names.
Islamic Hijri Calendar Date Converter
Convert any Gregorian date to the Islamic Hijri calendar and back with lunar month detail.
Julian to Gregorian Calendar Date Converter
Convert any historical Julian calendar date to its Gregorian equivalent, with the day-offset explained.
Mayan Long Count Calendar Converter
Convert Gregorian dates to Mayan Long Count calendar notation and back. Free online Mayan calendar converter with Tzolk'in and Haab' cycles included.
Roman Emperor Reign Timeline Comparator
Compare Roman Emperor reign lengths side-by-side. Explore all emperors from Augustus to Romulus Augustulus with interactive timeline bars and reign statistics.