Julian ↔ Gregorian Date Converter

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Age CalculatorCousin CalculatorJulian / GregorianOS/NS ConverterRoman NumeralsPerpetual CalendarCensus Age
The Julian calendar drifted from the solar year by about 11 minutes annually. By 1582 this had accumulated to 10 days, growing to 13 days by the 1900s. This calculator converts a specific date between the Julian and Gregorian calendars by applying the correct day correction for the century entered.

This is most relevant to records predating your ancestor's country adoption of the Gregorian calendar. A date recorded as "3 March 1700" in a Julian record may actually be "14 March 1700" in modern reckoning. The adoption dates below indicate when each country made the switch:
Most of Catholic Europe: 15 October 1582 (papal decree)
Scotland: 1 January 1600
England & Wales: 14 September 1752
Russia: 1918
Greece: 1923 (last European country)
Common examples
1588MDLXXXVIIISpanish Armada
1776MDCCLXXVIUS Independence
1888MDCCCLXXXVIIILongest Roman numeral ≤1999
1945MCMXLVEnd of WWII
1752MDCCLIIGregorian adoption (England)
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Enter the recorded age.