How to calculate a Hebrew yahrzeit date: Adar, nightfall and common questions
Many people know the civil date of a passing but not the Hebrew one, and when a leap year arrives, or when the passing was close to sunset, questions come up. Here we go through the accepted rules step by step.
Why the Hebrew date
A yahrzeit is set by the Hebrew calendar, not the civil one, because that is how it has been kept for generations. The civil date shifts every year relative to the Hebrew date, so a person who lit a candle on November 12 one year will need to light on a different date the next year. So the first step is to convert the date of passing to a Hebrew date.
To convert, you can use the yahrzeit candle button on this site, a Hebrew date converter, or a printed Hebrew calendar. Enter the civil date of the passing and you get a Hebrew date such as the 23rd of Tishrei, which you keep for all the years to come.
A passing after nightfall
This is one of the most common questions. The Hebrew day begins at night, so someone who passed away at night, after dark, has the Hebrew date of the following day. For example, a person who passed away at 8:30 on a Tuesday night when sunset was at 6:00 has a Hebrew date that belongs to Wednesday.
It is more complicated when the passing was between sunset and nightfall, which is about 20 minutes to an hour after sunset, depending on custom and location. In that case do not decide on your own. Ask a rabbi which date applies.
Adar and a leap year
In a leap year there are two months of Adar, Adar I and Adar II. Someone who passed away in Adar in a regular year, one with a single Adar, observes the yahrzeit in a leap year in Adar II, following the Rema. Someone who passed away in Adar I of a leap year observes in Adar I in later leap years, and in Adar in a regular year. Someone who passed away in Adar II of a leap year observes in Adar II in a leap year and in Adar in a regular year.
Customs vary in some cases, mostly in Sephardi communities. For example, some light twice, in both Adars, in a leap year. When in doubt, ask a rabbi or follow your family custom.
Cheshvan and Kislev, months of 29 or 30 days
The months of Cheshvan and Kislev vary. In some years they have 29 days and in others 30. If a person passed away on the 30th of Cheshvan or Kislev, and in a given year that month is short, there is no thirtieth day. In that case people commonly observe the yahrzeit on the first of the following month, which is Rosh Chodesh, and some observe on the 29th. It is a matter of custom, so ask a rabbi.
Someone who passed away on Rosh Chodesh, in a month with two days of Rosh Chodesh, observes on the actual day of passing. If it was the first day, the same day. If it was the second day, which is the thirtieth of the previous month, the second day.
The first yahrzeit
The first yahrzeit comes when one Hebrew year has passed from the day of passing. The rule is to count from the day of passing, not the day of burial. In a leap year, the first year ends on the same Hebrew date, unless the passing was in Adar, in which case the rules above apply.
Remember that mourning for a parent lasts twelve Hebrew months, but Kaddish is said for eleven months only, so as not to imply that the departed needs a full year of judgment. The first yahrzeit marks the end of the year of mourning.
When the date is unknown
If you do not know the Hebrew date, for example for someone who passed away long ago, try the cemetery records, the death certificate, the burial society, or your community rabbi. If you cannot find out, you may observe the Tenth of Tevet, or choose another day with your rabbi. If someone has forgotten the date, the custom is to choose one fixed day and keep it.
Examples
- A person who passed away during the day on the 23rd of Tishrei: light every year on the evening before the 23rd of Tishrei, whatever the civil date.
- A person who passed away in Adar in a regular year: in a leap year observe in Adar II, following the Rema.
- A person who passed away at midnight, after sunset and after nightfall: follow the next Hebrew day.
- A person who passed away on Shabbat: light on Friday, before Shabbat begins, since a flame may not be kindled on Shabbat.
How the site helps
With the yahrzeit candle button on the main screen you can save names and Hebrew dates, see when the next yahrzeit falls for your location, and add reminders to your phone's calendar ten years ahead. The calculation is done on your device and the information stays with you. For complex cases, such as Adar in a leap year or a passing close to sunset, please verify the date with a rabbi.
Questions and answers
How do I calculate a yahrzeit date?
Convert the civil date of the passing to a Hebrew date, and light every year on that Hebrew date, starting on the evening before.
What is the date if the passing was after sunset?
The Hebrew day begins at night, so a passing after dark belongs to the next Hebrew day. If it was between sunset and nightfall, ask a rabbi.
When is the yahrzeit if the person passed away in Adar?
In a leap year, someone who passed away in Adar of a regular year observes in Adar II, following the Rema. Someone who passed away in Adar I of a leap year observes in Adar I.
What if the passing was on the 30th of Cheshvan or Kislev?
In a year when the month is short, people usually observe on the first of the next month. Some observe on the 29th. Ask a rabbi.
What if the date of passing is unknown?
Check with the burial society or the cemetery. If it cannot be found, you can choose a day with a rabbi or observe the Tenth of Tevet.
Is the yahrzeit by the day of passing or burial?
By the day of passing, not the day of burial.
How long is Kaddish said for a parent?
Kaddish is said for eleven months, and mourning lasts twelve months. After that, Kaddish is said on each yahrzeit.
More guides
- The yahrzeit candle: what it is, when to light it, and how
- Yizkor and memorial candles on the holidays: the four times of the year
- When Shabbat ends: nightfall, 8.5 degrees and Rabbeinu Tam