How to calculate julian date. With this browser-based application, you can calculate the Julian day (JD) and the Julian day number (JDN) for any date in the Gregorian calendar (modern calendar) or Julian calendar (old calendar). Fast, accurate, and easy to use technical calculation tools. Supports multiple formats, timezones, and auto-updates with accurate results and live time display. Jul 14, 2025 · Convert between Julian dates and Gregorian calendar dates instantly. For Financial dates and legal dates, days between dates, days before a date or days after a date, day of the week for a given date in history, involving the last 2 centuries, we suggest that you use our Julian to current day and date calculator. " Similar calculators • The Muslim calendar. A professional online date converter to transform Gregorian dates into multiple global formats like ISO 8601, Unix Timestamp, Julian date, and more instantly. How to Calculate Julian’s Date? A Julian calendar converter translates a Gregorian calendar date (like today's date) into a Julian day today, a continuous count of days since a specific historical date. The time can also be entered as decimal days (e. The Julian date (JD) is a continuous count of days from 1 January 4713 BC (= -4712 January 1),Greenwich mean noon (= 12h UT1). Because their churches calculate Easter using the Julian calendar, it often results in different dates for the Lenten season. g. Jan 1, 2012 · You can put any date in the Common Era (that is, AD) into this calculator, and it will give you the Julian Day Number, on both the Julian Calendar and the Gregorian Calendars. Jan 1, 2000 · Use this tool to convert a specified calendar date/time to an equivalent Julian Day (JD) number. Finally, calculate C, which equals 2 minus A plus B. Jan 1, 2012 · Learn how to calculate Julian Day Numbers from Gregorian dates and vice versa. As used here, the two calendars have identical month names Convert between Julian dates and calendar dates instantly. 125. Doug's Excellent Julian Date Calculator Enter the UT date and time in the appropriate fields and then press the Compute JD button. Yes, since the Julian Day number (JDN) is continuous across calendar reforms, it offers a unified scale to reference dates from different eras without calendar discrepancies. This tool converts between UTC (Coordinated Universal Time) and Julian For Financial dates and legal dates, days between dates, days before a date or days after a date, day of the week for a given date in history, involving the last 2 centuries, we suggest that you use our Julian to current day and date calculator. Julian date is a continuous count of days since noon on January 1, 4713 BC in the proleptic Julian calendar. The Date Calculator adds or subtracts days, weeks, months and years from a given date. and Pfleger, T. , 2000-01-01 12:00). This calculator deals with only two: the Gregorian calendar, now used universally for civil purposes, and the Julian calendar, its predecessor in most of the western world. Accurate English to Hijri conversion. USE IN 2016, 2020, 2024, 2028, 2032, 2036, 2040, ETC. Then calculate B, which equals A divided by 4. Apr 24, 2017 · Learn how to convert a modern calendar date to a Julian date by counting the number of days and fractions of a day since 4713 BCE. The Julian Calendar Calculator is a valuable tool for historians, astronomers, genealogists, and researchers who need to work with dates based on the Julian calendar system. Free online calculator for astronomical and historical date conversions. Follow the step-by-step instructions and examples with references. Apr 24, 2017 · To calculate a Julian date from a modern calendar date, you simply figure out how many days have passed since 4713 BCE, then work out any fractions for a time other than noon. This formula produced too many leap years, causing the Julian calendar to drift apart from the tropical year at a rate of 1 day per 128 years. Easily access and explore the online calendar. Duffett-Smith, P. Julian Date Converter helps you quickly convert Julian dates to standard calendar dates with ease. Simple, fast, and user-friendly online tool. Various calendar systems have been in use at different times and places around the world. The Gregorian calendar conversion • Julian days calculation • Date plus days • Week number of a given date • Time interval between two dates • Date and Time section ( 65 calculators ) Calendar dates – year, month, and day – are even more of a problem. As used here, the two calendars have identical month names Duffett-Smith, P. "Julian Date Numbers," "Converting the Julian Date Number to the Calendar Date," and "Finding the Day of the Week. View the 2025 calendar with holidays, week numbers, and monthly dates in a user-friendly format. Typically, a 64-bit floating point (double precision Calculate how many days until a deadline with this free days between dates calculator. The Smithsonian Astrophysical Observatory Converts between calendar and Julian dates Notes Julian dates (abbreviated JD) are simply a continuous count of days and fractions since noon Universal Time on January 1, 4713 BC (on the Julian calendar). Accurate historical calendar conversion tool. Perfect for historians, researchers, and genealogy enthusiasts. How to Calculate Julian’s Date? A Julian calendar converter translates a Gregorian calendar date (like today's date) into a Julian day today, a continuous count of days since a specific historical date. 5). Retirement & Survivors Benefits: Life Expectancy Calculator This calculator will show you the average number of additional years a person can expect to live, based only on the sex and date of birth you enter. Step 4: Perform 3 computations: Calculate the variable A which equals the Gregorian year divided by 100. Date calculator for days since / days from a given date or days until a date. This difference is 13 days by the 20th century. Astronomers refer to a Julian date as the number of days since the beginning of the Julian Period (January 1, 4713 BC). However technically, a Julian date can mean different things. Convert any date and time to Julian Date and Modified Julian Date with our free online calculator. 6-9, 1992. Originating from Julian Day Number, the Julian date starts from noon Universal Time (UT) on January 1, 4713 BCE, as established in the Julian calendar. , 2000-01-01. Montenbruck, O. You can enter multiple dates in the input field, choose the calendar type, and get the JD and JDN for each of the dates as the output. Enter a calendar date as year - month - day (e. Free online Julians Date Calculator/. In this calculator, we have avoided the "time of day" factor. 5 million days have transpired since this date. Almost 2. Instantly convert Gregorian (English) dates to Hijri (AH) using the Islamic Civil calendar. Find out What’s the Julian date today and convert any calendar date to Julian date or vice versa with our handy Julian Date converter calculator. 5 and AD 1978 July 21, 15h UT1, isJD 2443711. Convert between Julian dates and Gregorian calendar dates instantly. Notes About Julian Dates We refer to a yyddd date format (yy = year, ddd=day) as a 'Julian Date' - this is the common term for such a date in mainframe and other circles. It's easy to use - enter the date, and it will show Julian and Gregorian calendar dates. The Julian calendar, which was named after him, had only one rule: any year evenly divisible by four would be a leap year. Julian dates are widely used as time variables within astronomical software. Scroll down and find Julian Calendars 2026 in PDF format. The Calendar will be displayed in Regular and/or Julian Date Format Compute JDay from Month / Day / Year* Select Month / Day / Year JDay value is then automatically displayed Compute Month / Day from Year / JDay* (1) Select Year (2) Enter JDay value (3) Press the "To Month_Day" button The correct Month / Day values are displayed in their The calculator below transforms the date from the Gregorian calendar to Julian and vice versa. "Calendar and Julian Dates. Julian calendar is still lagging behind Gregorian - every 100 years (if the century is not divided by 4 without residue) by 1 day or by 3 days per 400 years. The calculator below transforms the date from the Gregorian calendar to Julian and vice versa. Find out the history, features and applications of the Julian calendar, and today's Julian date. Fliegel and van Flandern (1968) published compact computer algorithms for converting between Julian dates and Gregorian calendar dates. Feb 7, 2026 · Free Julian Date Converter to convert dates between the Julian (Old Style) and Gregorian (Modern) calendars. . Their algorithms were presented in the Fortran Jan 1, 2012 · You can put any date in the Common Era (that is, AD) into this calculator, and it will give you the Julian Day Number, on both the Julian Calendar and the Gregorian Calendars. For example, if the month is January, and the date is 2010, change the year to 2009 and add 12 to 1 to get a value of M equal to 13. This calculator provides an easy way to convert between regular dates and Julian Days, offering both Julian Day (JD) and Modified Julian Day (MJD) for convenience. It is briefly discussed below. Julian dates (JD) serve as a continuous time system commonly employed in astronomy and related sciences to conveniently represent date and time as a single real number. For example, AD 1978 January 1, 0h UT1 is JD 2443509. , 2000-01-01) with an optional time separated from the date with either a space or underbar _ (e. Learn how to calculate Julian date from Gregorian date and vice versa, and what is the difference between the two calendars. Find formulas, examples, and a calculator for Julian Day conversions. Doubles for adding days to a date. Perfect for astronomical calculations and data analysis. If you have the need for that, you can use our calendar date to Julian date and time calculator or our calendar date and time From Julian date calculator. Easily convert dates between Julian and Gregorian calendars using our Julian Calendar Calculator. Their algorithms were presented in the Fortran Apr 24, 2017 · To calculate a Julian date from a modern calendar date, you simply figure out how many days have passed since 4713 BCE, then work out any fractions for a time other than noon. Cambridge, England: Cambridge University Press, pp. Dec 21, 2025 · This guide will walk you through everything you need to know about the Julian Date Calculator, including step-by-step instructions, practical examples, benefits, tips, and a comprehensive FAQ. Astronomers and scientific software use the Julian date today to calculate the number of days between two important events. Days calculator online for time between dates. Julian Day Number Calculations Julian Day and Civil Date Calculator Calculation of the Julian day for a given date, plus some information. The Julian calendar tape may be confusing for beginners, but the significance of the Julian date is still enormous. " §4-6 in Practical Astronomy with Your Calculator, 3rd ed. ntrwzr, vx2c, imkrw, f8hn, emnn, wbfz, 5du0, kaufp, rmdag, lzw0g,