General Resource Sites

• Brenda's Branches - Time Period Approximation Chart 
  Helps you to determine time periods to search in with limited data to begin the search.
• Calendars and Their History 
• Calendars Through The Ages 
  Explore the fascinating history of the human endeavor to organize our lives in accordance with the sun and stars.
• Calendar Zone 
• Calendopaedia - The Encyclopaedia of Calendars 
  History & information on a variety of calendar systems.
• Chronology and Dating 
• Hermetic Systems: Calendar Studies 
• Historic Calendars of Europe 
  A form to generate the type of calendar used for a particular year.
• A History of the Western Calendar 
• History & info - the Islamic calendar 
• Index of Russian Dates & Calendar Terms 
  In order to find and use specific types of Russian records, resarchers need to be able to identify and understand some key terms in the Russian language. This glossary contains terms relating to dates, time and calendars in Imperial Russia, transliterated from Russian, along with their English translations. Theterms included here are those that you are likely to find in Russian genealogical sources.
• Marking Time - A History of the Months and the Meanings of their Names 
• A Medieval English Calendar 
  This is a version of the Julian calendar, as used in England, covering the 11th to 16th centuries.
• One-Step Webpages by Stephen P. Morse 
  Alternate search functions for many online databases. Includes tools for immigration, census, vital records, calendars, soundex, foreign alphabets, Jewish and Holocaust research.
  • Calendar, Sunrise/Sunset, Maps 
• Past Mardi Gras Dates  ~ New Orleans, Louisiana
• Persian Calendar 
• Regnal Chronologies 
  A calendar of worldwide royal reigns, arranged geographically. The study of of king lists, sequences of governance in the history of a state, and the organizing of such data.
• Sizes: The Online Quantinary 
  • Index to Time and Calendars 
• A Summary of the International Standard Date and Time Notation 
  International Standard ISO 8601 specifies numeric representations of date and time. This standard notation helps to avoid confusion in international communication caused by the many different national notation.
• Table of Dates Given in Terms of Year of Monarch's Reign 
  Table to convert the old English system (i.e., typical of old English documents) of "year of monarch's reign" to year A.D.
• 3 Charts for Date to Day of the Week Conversions 
  From the ROOTS-L Library: Dates and Calendars.
• Yahoo!...Reference...Calendars 

Birthdate Calendars and Calculators

• BirthCalc 
  Palm utility for determining birthdates when only the date of death and age are known.
• Birthdate Calculator 
• Birth Date Calculator 
• Birth Date Calculator 
• Birthdate CalculatorJavaScript Birthdate Calculator 
• Birthdate CalculatorJavaScript Birthdate Calculator 
• Buckner's Birthdate Calculator 
  Calculates birthdate from death date and age of death in day/month/year format.
• Calculate Birthdate from Death Data 
• Calculating Birth Year Based on Census Information 
• Calendar Calc for Mac OS - Peter LEWIS Software 
  Help calculate a person's birth date when looking at census records or marriage certificates. All UK, US and Canadian census years are included.
• Date Calculator - An Aid for Family Historians 
  Freeware which assists Family Historians in calculating dates from any two of the three following elements Birth Date, Event Date, Age at Event.
• Day of Week Born 
• Determining Date of Birth - "Formula 8870" 
• JavaScript Birthdate Calculator 
• My Relative - Day of Date Calculator 
• The Olive Tree Genealogy: Date of Birth Calculator 
• Tombstone Birthday Calculator 
  Tombstone Calculator computes birthdate from age and date of death.
• VGS Birthdate Calculator 
  From the Victoria Genealogical Society in British Columbia, Canada.

Calculators & Converters

• 10,000-Year Calendar 
  Choose menu options and view a month or year calendar for any year 1 to 10000 A.D.
• CalendarHome.com Calendar Converter 
• Calendar Conversions 
  Scott Lee's free on-line service for converting to/from dates in Gregorian, Julian, French republican and Jewish calendars.
• Calendar Converter 
  Converts dates between Julian, Gregorian, Hebrew and French Calendars and Julian Date.
• Calendar Converter 
  Gregorian, Julian, Hebrew, Islamic, Persian, Mayan, French Republican, and more.
• Calendar Form 
  Type in a month and year - future or past - and it returns a calendar of that month.
• Convert between Old & New Style dates 
• Day of the Week Calculator 
• GEDCOM Date Calculator 
  A free utility for converting dates between Gregorian, Julian, Hebrew, and French Republic calendars and for doing calculations on dates such as finding time spans or adding and subtracting time spans to dates. The Date Calculator is available for MacOS or Windows. The Date Calculator can work with "fuzzy" dates (such as just a year and a month) and still do conversions and calculations. Such "fuzzy" date calculations are useful for genealogists working with less than complete date information.
• The Gregorian Calendar Conversion 
• Ian's English Calendar 
  Interactive calendar helps you calculate: Ecclesiastical Calendar, Old and New Style Dating, Day of the Week, Regnal Years.
• Julian Day and Civil Date Calculator 
• Regnal Year Calculator 
• time and date.com Calendar 
  Conversion option allows you to enter any year and generate the calendar on the fly.
• Tom Nunamaker's Census Age Calculator 
  For UK census years.

Census Years

• Birth Year Calculations - Calculating Birth Year Based on Census Information 
• Census Dates for Countries and Areas of the World: 1946 to 2004 
  Shows the dates of census enumerations over the past half century, as well as projected or scheduled enumerations in the near future. for countries around the world.
• Tom Nunamaker's Census Age Calculator 
  For UK census years.
• UK Census Dates 
• UK Census Dates 
• UK - Census Dates 

Chinese Calendar

• Chinese Calendar 
• Western-Chinese Calendar Converter 

French Republican Calendar

• Beyond the Index--Michael John Neill--Dating the Belgians via France 
  This article discusses the French Republican calendar, used for several years after the French Revolution in France and areas under France's jurisdiction.
• FamilySearch.org - Research Outline - French Republican Calendar 
• The French Republican Calendar 
  History of the French republican calendar and conversions to the Gregorian calendar. Official texts. Great dates. In French and English.
• French Revolutionary Calendar 
  Online conversion of any date since 1792.
• French Revolutionary Calendar 
• GEDCOM Date Calculator 
  A free utility for converting dates between Gregorian, Julian, Hebrew, and French Republic calendars and for doing calculations on dates such as finding time spans or adding and subtracting time spans to dates. The Date Calculator is available for MacOS or Windows. The Date Calculator can work with "fuzzy" dates (such as just a year and a month) and still do conversions and calculations. Such "fuzzy" date calculations are useful for genealogists working with less than complete date information.
• Genealogy in France: Republican Calendar 
  Also known as "French Revolutionary Calendar", this calendar was in used in France from 1793 to 1805, and 1871 (only in Paris).
• Revolution 
  Software utility for the Palm that converts dates in the French Republican calendar to the Gregorian calendar.
• Rosetta Calendar - A Calendar Conversion Service 
  Scott Lee's free on-line service for converting to/from dates in Gregorian, Julian, French republican and Jewish calendars.
• Universal Calendar Calculator 
  The Universal Calendar Calculator can display and convert between 10 different calendars: Julian Day Number, Gregorian (New Style), Julian (Old Style), Roman-Julian, French Revolution, Hebrew, Islamic, Chinese, Chinese/Gregorian, and Thai Suriyakati Calendar. The Universal Calendar Calculator also contains: * Dates of holidays for the United States, Christian (Nicean Rule and Modern), Islamic, Jewish, and Chinese. * Regional date of conversion from the Old Style (Julian) to the New Style (Gregorian) for more than 100 localities. * Almost 100 Medieval European Regional Day Name Calendars. These calendars allow you to easily identify the specific Julian Calendar day of many Latin day names given in Medieval documents.

Leap Years

• Leap Year, 1582-1752 (a query) 
• Leap Years and Our Calendar 

Old Style & New Style: Julian to Gregorian

• Convert between Old & New Style dates 
• Gregorian Calendar 
• Gregorian Calendar - Wikipedia 
• The Gregorian Calendar Conversion 
• Julian Calendar - Wikipedia 
• The National Archives | Palaeography tutorial - Quick reference: Calendar Years  ~ United Kingdom
  Explains the pre-decimal English currency system.
• Old Style and New Style Dates and the Change to the Gregorian Calendar - A Summary for Genealogists 
  By Mike Spathaky.
• Old Style - New Style Reference 
  By entering any year, a side-by-side calendar is generated showing the Old Style dates on top with the New Style dates on the bottom for each day of the week for each month of the year. Very handy for counting days in one Style or the other but this calendar calculator does not include any Style change over information.
• Perpetual Calendar 
  Provides a brief explanation of the switch from Gregorian to Julian. Also gives a very detailed table which shows by nation and district, when the change from Old Style to New Style happened. This table is extremely useful.
• Wikipedia, the free encyclopedia - Old Style and New Style Dates 

Perpetual Calendars

• Another Perpetual Calendar 
  From the ROOTS-L Library: Dates and Calendars.
• GENUKI: Dates of Easter Sunday and Perpetual Calendar, 1550-2049 (for Great Britain and the Colonies) 
• Notre Dame Archives - Perpetual Calendar 
  What's valuable (and different) about this perpetual calendar is that it has a calculator which enables you to find appropriate years when you know only the day of the week, the date, and the month.
• A Perpetual Calendar 
  From the ROOTS-L Library: Dates and Calendars.
• Perpetual Calendar 
• Perpetual Calendar 
  Perpetual calendar, including dates for holidays and leap years.

Publications, Software & Supplies

• Cyndi's List Genealogy Bookstore 
  A categorized list of genealogy research books that looks a lot like my bookshelf at home.

• Calendar Creation Software 
• Calendar : Humanity's Epic Struggle to Determine a True and Accurate Year 
  A book by David Ewing Duncan. An excellent general history of how we order the days as we do. Great background reading for genealogists struggling with the changes to our calendar in history.
• Calendar Pal 1.0.2 
  For Palm OS. Monthly view of Gregorian, Hebrew, Islamic, Julian, or Persian calendar.
• Calisto 
  A free calendar program (W95+ and DOS) to display British calendar 1-2999 with holy days and monarchs. Compares Julian, Gregorian, Jewish, Islam, European dates.
• Date Calculator 
  By Acute Software. Simple utility to calculate the number of days, weeks, months or years between any two dates.
• Date Calculator 
  Windows software to perform date-related calculations. Determine someone's age from birthday date, number of days between two dates & more.
• Dictionary of Saints Days, Fasts, Feasts & Festivals 
  A book by Colin Waters.
• GEDCOM Date Calculator 
  A free utility for converting dates between Gregorian, Julian, Hebrew, and French Republic calendars and for doing calculations on dates such as finding time spans or adding and subtracting time spans to dates. The Date Calculator is available for MacOS or Windows. The Date Calculator can work with "fuzzy" dates (such as just a year and a month) and still do conversions and calculations. Such "fuzzy" date calculations are useful for genealogists working with less than complete date information.
• Genealogical dates: A user-friendly guide 
  A book by Kenneth L. Smith.
• A Handbook of Dates : For Students of British History 
  A book by C. R. Cheney.
• The Oxford Companion to the Year 
  A book by Bonnie Blackburn.
• Revolution 
  Software utility for the Palm that converts dates in the French Republican calendar to the Gregorian calendar.

Quaker Calendar

• Old Style & New Style Dates for the Quaker Calendar 
  From the ROOTS-L Library: Dates and Calendars.
• Ancestry.com - Time to Take Note: The 1752 Calendar Change 
  Article by Kip Sperry. Read the section on Quaker Dating.

Religious Calendars

• 50 Year Yahrzeit Calendar Calculator 
• Calculate the Date of Easter & Other Moveable Holidays 
• Calculation of the Ecclesiastical Calendar 
• Catholic Calendar Page 
• The Christian Year 
  Calculates the dates of moveable feasts according to the Church of England for any year and provides a days of the week calendar for that year as well.
• Conversion of Islamic and Christian Dates 
• The Date of Easter 
• The Date of Easter 
  Time Fact Files from the Royal Greenwich Observatory.
• Dates of Easter, Rosh Hashanah and Passover 
• GENUKI: Dates of Easter Sunday and Perpetual Calendar, 1550-2049 (for Great Britain and the Colonies) 
• Determining the Date of Easter 
• Easter Dating Method 
• Easter Sunday Dates 
• English Calendar 
  Interactive calendar helps you calculate: Ecclesiastical Calendar, Old and New Style Dating, Day of the Week, Regnal Years.
• Judaism 101: Jewish Calendar 
• Liturgical Year - Wikipedia, the free encyclopedia 
• Old Style & New Style Dates for the Quaker Calendar 
  From the ROOTS-L Library: Dates and Calendars.
• On-line Calendar of Saints Days 
• A Simplified Easter Dating Method 
• Useful Dates in British History - Special Days in the Year 
  Traditional "Feast" days from the UK calendar.
• Yahrzeit Calendar 
  Converts Gregorian to Hebrew dates and vice versa. Gives Yizkor dates through 2012.

Roman Numerals

• Legion XXIV - Roman Numerals Page 
• Online Conversion - Advanced Roman Numeral Converter 
• The Roman Art of Counting 
• Roman Digits 
• Roman Numeral and Date Conversion with Roman Calculator & Test 
• Roman Numeral / Arabic Numeral Conversion 
• Roman Numeral Conversion and Self Test< 
• Roman Numerals Converter 
• Roman Numeral Dates | Conversion Guide 
• Roman Numerals and Calendar 
  A list of dates converted Arabic numerals to Roman numerals for the years 1450 to 2100.
• Roman Numerals 
  Includes a Handy Roman numeral converter.

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