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How to make changes to a Yahrzeit + Anniversary calendar

This article describes how to make changes to a Yahrzeit + Anniversary calendar that you downloaded, exported or subscribed to in a calendar app like Outlook, Google Calendar / Android, or Apple (iOS, iPhone, iPad or Mac). These instructions apply to personal events such as yahrzeits, Hebrew Birthdays, and Hebrew Anniversaries.

1. I have a Hebcal calendar feed subscription

If you used Hebcal to create your personal calendar after August 2020 and you subscribed using the recommended feed option, you can click on the hebcal.com URL at the bottom of a calendar event. That link will take you back to the Yahrzeit and Anniversary calendar where you can make edits to each person’s name or dates.

2. I have a Hebcal annual email reminder subscription

If you subscribed to annual email reminders and did not synchronize your Apple/Google/Outlook calendar, you will find an “Edit Yahrzeit” link at the bottom of the reminder email message.

example email message including edit link

For a birthday, the link will be titled “Edit Hebrew Birthday.” For an anniversary, the link will be titled “Edit Hebrew Anniversary.”

3. I don’t have a separate calendar feed; I merged Hebcal anniversary events into my regular personal calendar

You may have downloaded yahrzeit/anniversary events and merged them into your regular personal calendar (often called “Home” or “Calendar”). To remove those events, search for the event(s) in your regular calendar and remove/delete them one at a time. These events will always have one of the following titles: “Yahrzeit”, “Hebrew Birthday” or “Hebrew Anniversary”.

Once you have removed the yahrzeit/anniversary calendar events, return to Hebcal.com and re-enter in all of the event details, then download again.

4. I subscribed to a calendar feed before August 2020

If you subscribed before August 2020, you will need to delete or unsubscribe the calendar containing your yahrzeit and anniversary reminders. Hebcal personal event calendars created before this date do not support editing event dates or names. Directions for how to delete/remove a subscribed calendar vary by calendar application. 

Yahrzeit + Anniversary REST API

We are pleased to offer support for REST API for personal Yahrzeits, Hebrew Birthdays and Hebrew Anniversaries.

Clients should POST x-www-form-urlencoded data to https://www.hebcal.com/yahrzeit

The following parameters must be specified

  • cfg=json
  • v=yahrzeit

The following parameters may be specified once

  • years=3 – default 20. Use years=1 for only a single Hebrew year
  • hebdate=on – append Hebrew date to the event titles (default off)
  • yizkor=on – Include Yizkor dates (default off)
    • i=off – Diaspora Yizkor schedule (Pesach 8th day, Shavuot 2nd day, Yom Kippur and Shmini Atzeret)
    • i=on – Israel Yizkor schedule (Pesach 7th day, Shavuot, Yom Kippur and Shmini Atzeret)
  • start=5749 – beginning Hebrew year to calculate anniversary dates (defaults the current Hebrew year)
  • end=5761 – ending Hebrew year (inclusive) to calculate anniversary dates (defaults to start year + years years)

Then, specify at least one input date based on the Gregorian date of death (or birth). The following parameters are required, substituting the X with increasing integers beginning with 1.

  • yX=1983 – Gregorian year, 4-digit date
  • mX=4 – Gregorian month (1=January, 12=December; leading zeros optional)
  • dX=15 – Gregorian day of month (1-31; leading zeros optional)
  • sX=on – Event occurred on Gregorian date after sunset (default off implies that event occurred before sunset)
  • tX=Yahrzeit – type (either Yahrzeit, Birthday or Anniversary – case-sensitive)
  • nX=Plonit+ben+Ploni – name (optional)

Please take care to specify the correct tX type parameter (either Yahrzeit, Birthday or Anniversary). The algorithm (according to Ashkenazic practice) differs between these options, especially in the months of Adar, Cheshvan, or Kislev. For more information, see “How does Hebcal determine anniversaries (birthdays, yahrzeits)?

Unlike other Hebcal.com REST APIs, this API requires HTTPS (either HTTP/1.1 or HTTP/2) due to the personal/sensitive nature of the information being passed across the Internet.

  • We support both gzip and br (brotli) compression; set the appropriate Accept-Encoding header in your request to enable
  • We support HTTP Keep-Alive for multiple requests

Example

Here is an example of two events, a Hebrew Birthday for Person1 and a Yahrzeit for Person2:

curl \
  -X POST \
  -H 'Content-Type: application/x-www-form-urlencoded' \
  --compressed \
  --data-raw 'cfg=json&v=yahrzeit&n1=Person1&t1=Birthday&d1=15&m1=4&y1=1983&s1=on&n2=Person2&t2=Yahrzeit&d2=13&m2=11&y2=2008&s2=off&hebdate=on&years=3' \
  https://www.hebcal.com/yahrzeit

The response will be application/json that looks like this:

{
  "title": "Hebrew Anniversaries: Person1, Person2",
  "date": "2022-05-30T19:04:58.561Z",
  "range": {
    "start": "2021-10-21",
    "end": "2024-05-11"
  },
  "items": [
    {
      "title": "Person2's 13th Yahrzeit (15th of Cheshvan)",
      "date": "2021-10-21",
      "hdate": "15 Cheshvan 5782",
      "memo": "Hebcal joins you in remembering Person2, whose 13th Yahrzeit occurs on Thursday, October 21, corresponding to the 15th of Cheshvan, 5782.\n\nPerson2's Yahrzeit begins at sundown on Wednesday, October 20 and continues until sundown on the day of observance. It is customary to light a memorial candle at sundown as the Yahrzeit begins.\n\nMay your loved one's soul be bound up in the bond of eternal life and may their memory serve as a continued source of inspiration and comfort to you.",
      "name": "Person2",
      "category": "yahrzeit",
      "anniversary": 13
    },
    {
      "title": "Person1's 39th Hebrew Birthday (3rd of Iyyar)",
      "date": "2022-05-04",
      "hdate": "3 Iyyar 5782",
      "memo": "Hebcal joins you in honoring Person1, whose 39th Hebrew Birthday occurs on Wednesday, May 4, corresponding to the 3rd of Iyyar, 5782.\n\nPerson1's Hebrew Birthday begins at sundown on Tuesday, May 3 and continues until sundown on the day of observance.",
      "name": "Person1",
      "category": "birthday",
      "anniversary": 39
    },
    {
      "title": "Person2's 14th Yahrzeit (15th of Cheshvan)",
      "date": "2022-11-09",
      "hdate": "15 Cheshvan 5783",
      "memo": "Hebcal joins you in remembering Person2, whose 14th Yahrzeit occurs on Wednesday, November 9, corresponding to the 15th of Cheshvan, 5783.\n\nPerson2's Yahrzeit begins at sundown on Tuesday, November 8 and continues until sundown on the day of observance. It is customary to light a memorial candle at sundown as the Yahrzeit begins.\n\nMay your loved one's soul be bound up in the bond of eternal life and may their memory serve as a continued source of inspiration and comfort to you.",
      "name": "Person2",
      "category": "yahrzeit",
      "anniversary": 14
    },
    {
      "title": "Person1's 40th Hebrew Birthday (3rd of Iyyar)",
      "date": "2023-04-24",
      "hdate": "3 Iyyar 5783",
      "memo": "Hebcal joins you in honoring Person1, whose 40th Hebrew Birthday occurs on Monday, April 24, corresponding to the 3rd of Iyyar, 5783.\n\nPerson1's Hebrew Birthday begins at sundown on Sunday, April 23 and continues until sundown on the day of observance.",
      "name": "Person1",
      "category": "birthday",
      "anniversary": 40
    },
    {
      "title": "Person2's 15th Yahrzeit (15th of Cheshvan)",
      "date": "2023-10-30",
      "hdate": "15 Cheshvan 5784",
      "memo": "Hebcal joins you in remembering Person2, whose 15th Yahrzeit occurs on Monday, October 30, corresponding to the 15th of Cheshvan, 5784.\n\nPerson2's Yahrzeit begins at sundown on Sunday, October 29 and continues until sundown on the day of observance. It is customary to light a memorial candle at sundown as the Yahrzeit begins.\n\nMay your loved one's soul be bound up in the bond of eternal life and may their memory serve as a continued source of inspiration and comfort to you.",
      "name": "Person2",
      "category": "yahrzeit",
      "anniversary": 15
    },
    {
      "title": "Person1's 41st Hebrew Birthday (3rd of Iyyar)",
      "date": "2024-05-11",
      "hdate": "3 Iyyar 5784",
      "memo": "Hebcal joins you in honoring Person1, whose 41st Hebrew Birthday occurs on Saturday, May 11, corresponding to the 3rd of Iyyar, 5784.\n\nPerson1's Hebrew Birthday begins at sundown on Friday, May 10 and continues until sundown on the day of observance.",
      "name": "Person1",
      "category": "birthday",
      "anniversary": 41
    }
  ]
}

How does Hebcal determine anniversaries (birthdays, yahrzeits) in Adar, Cheshvan, or Kislev?

Calendrical CalculationsHebcal uses the anniversary algorithm defined in Calendrical Calculations by Edward M. Reingold and Nachum Dershowitz, which accords with Ashkenazic practice.

Birthday

Reingold and Dershowitz write:

The birthday of someone born in Adar of an ordinary year or Adar II of a leap year is also always in the last month of the year, be that Adar or Adar II. The birthday in an ordinary year of someone born during the first 29 days of Adar I in a leap year is on the corresponding day of Adar; in a leap year, the birthday occurs in Adar I, as expected. Someone born on the thirtieth day of Marcheshvan, Kislev, or Adar I has his birthday postponed until the first of the following month in years where that day does not occur. [Calendrical Calculations p. 111]

Yahrzeit

Yahrzeit refers to the anniversary, according to the Hebrew calendar, of the day of death of a loved one. Alternative spellings include yahrtzeityortsaytyartzeit. Yahrzeit is written יאָרצײַט in Yiddish, which translates to “time of year”; the Hebrew equivalent is נַחֲלָה, transliterated as nachala (“legacy,” or “inheritance”).

The rules for a Yahrzeit are a little different than for a birthday:

The customary anniversary date of a death is more complicated and depends also on the character of the year in which the first anniversary occurs. There are several cases:

  • If the date of death is Marcheshvan 30, the anniversary in general depends on the first anniversary; if that first anniversary was not Marcheshvan 30, use the day before Kislev 1.
  • If the date of death is Kislev 30, the anniversary in general again depends on the first anniversary — if that was not Kislev 30, use the day before Tevet 1.
  • If the date of death is Adar II, the anniversary is the same day in the last month of the Hebrew year (Adar or Adar II).
  • If the date of death is Adar I 30, the anniversary in a Hebrew year that is not a leap year (in which Adar only has 29 days) is the last day in Shevat.
  • In all other cases, use the normal (that is, same month number) anniversary of the date of death.

[Calendrical Calculations p. 113]

Yahrzeit Example

For example, suppose Ploni ben Ploni passed away on 14 March 2001. That date corresponds to the 19th of Adar, 5761. Since 5761 was not a leap year, there was only one Adar that year (i.e. the date of death occurred in 12th month of the Hebrew year).

Suppose one wishes to observe the yahrzeit in Hebrew year 5765. Since 5765 is a leap year and none of the other rules applies, we use the same month number as the date of death. In a leap year the 12th month is Adar I, so the yahrzeit is observed on 19th of Adar I, 5765 (28 February 2005).

Variations

On page 114, Reingold and Dershowitz write:

There are minor variations in custom regarding the anniversary date in some of these cases. For example, Spanish and Portuguese Jews never observe the anniversary of a common-year date in Adar I.

There are undoubtedly many differing opinions regarding when to observe an Adar yahrzeit.

Here are two articles which offer differing opinions from our implementation:

For all matters of halacha, consult your local rabbi.

Sources

Reingold and Dershowitz cite two sources:

The Comprehensive Hebrew Calendar, Arthur Spier, 3rd edition, 1986, pp. 5-7

Talmudic Encyclopedia: A Digest of Halachic Literature and Jewish Law From The Tannaitic Period to the Present Time Alphabetically Arranged, vol I (1951), p. 93; vol. XXIII (1997), cols 153-154

Updates

9 Feb 2005: added errata at Nachum Dershowitz’s request.
9 Mar 2005: Added Ploni ben Ploni example.
9 Mar 2014: Added links to opinions by Rabbis Golinkin and Schachter
28 Dec 2016: Corrected misspellings
3 Feb 2021: Added “Sources” section

Yahrzeit/Birthdays observed in Adar II

Last week I fixed a bug in yahrzeit calculations in the hebcal website.
Calendrical Calculations

According to Calendrical Calculations by Edward M. Reingold and Nachum Dershowitz, the yarhzeit of someone who passed away in Adar of an ordinary year or Adar II of a leap year is also always in the last month of the year, be that Adar or Adar II.

The hebcal.com website previously displayed those anniversaries as occurring in Adar I. Hebcal for Unix 3.3beta10 also contains this fix.