Calendars & Dates » Calculators & Converters

10,000-Year Calendar

Choose menu options and view a month or year calendar for any year 1 to 10000 A.D.

BCG Skillbuilding: Date Calculations

Calculate Dates Based on Regnal Years

Calculate the date of Easter & other moveable holidays

Calendar Calculator

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.

CalendarHome.com Calendar Converter

Conception Date Calculator New!

This tool calculates the date of conception based on a date of birth. This gives you context of when the two parents must have been present together. The calculator estimates that a pregnancy typically lasts 266 days. This isn’t exact but is based on known average intervals. The estimated date helps if you are trying to identify a father based on other information such as residency data or military service.

Convert between Old & New Style dates

Convert Regnal years to Calendar Years

Allows you to convert English monarch years to calendar years

Convertisseur de Calendriers

Day of the Week Calculator

Determining Time between Two Events in One Step (or Determining Birthdate from Deathdate and Age)

Estimate Life Events Dates

Javascript utility page. Input current age or year of birth, U.S. high school or college graduation or death. It generates a web page with charts showing estimated year of births, graduations, deaths for that person and parents. Assumes all dates are 31 December.

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.

GeneaMichaud : Rubrique T

Download a free dates conversion add-in for Excel (97 and above). Converts to/from Julian, Gregorian and French Republic calendars. Adds many new functions to Excel and access to database for France giving the climate since 1370, the sovereigns, wars, diseases.

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