And another way to calculate it is to convert to Gregorian and then use a date difference website:

https://www.hebcal.com/converter?hd=19&hm=Tamuz&hy=5744&h2g=1

19th of Tamuz, 5744 = Thu, 19 July 1984

https://www.hebcal.com/converter?hd=24&hm=Tishrei&hy=5784&h2g=1

24th of Tishrei, 5784 = Mon, 9 October 2023

Then visit the Days Calculator: Days Between Two Dates calculator

From and including: Thursday, July 19, 1984
To and including: Monday, October 9, 2023
https://www.timeanddate.com/date/durationresult.html?m1=10&d1=09&y1=2023&m2=07&d2=19&y2=1984&ti=on

Result: 14,327 days
It is 14,327 days from the start date to the end date, end date included.

Or 39 years, 2 months, 21 days including the end date.

Or 470 months, 21 days including the end date.

Hi, thanks for using Hebcal, and mo'adim l'simcha!

We're happy to continue to provide Torah Readings for holidays. You'll find them posted on the holiday page, for example

https://www.hebcal.com/holidays/sukkot-2023#reading

For the Israel version, visit this page:

https://www.hebcal.com/holidays/sukkot-2023?i=on#reading

Thank you for using the Hebcal Yahrzeit + Anniversary calendar. Moadim L'Simcha! We wish you a very happy Sukkot.

Yahrzeit always begins at sundown and continues until sundown on the day of observance. It is customary to light a memorial candle at sundown as the Yahrzeit begins.

If a Yahrzeit begins on Friday night, it's customary to light the yahrzeit candle before Shabbat begins. If a Yahrzeit begins on Saturday night, it is customary to light the yahrzeit candle after Havdalah.

If you subscribe to our email Yahrzeit reminders, you will receive a message one week before the anniversary. This message does not specify what time to light a yahrzeit candle. It does also include an optional calendar reminder, typically set for 16:30 local time on weekdays and 20:00 local time on Saturday night.

To avoid any possibility that someone might light a yahrzeit candle after Shabbat begins, we will make a change to our calendar reminders to have them start earlier (14:30 local time) for any yahrzeit occurring on a Friday.

Thanks for letting us know! There are multiple ways to transliterate the name of the holiday and both spellings are considered acceptable.

Thanks for posting that. From looking at the code snippet you sent, you are using the JSON Jewish calendar API.

The problem is in your code. This API returns dates and times using the standard ISO 8601 format. Dates will look like 2015-05-22T17:11:00-03:00

Check your application code and confirm that you are interpreting dates correctly with respect to the genonameid location you are using 

Hi, thanks for using Hebcal and the FullCalendar integration. We're sorry to hear that the page is very slow.

We have an experimental approach that uses the Hebcal JavaScript APIs (instead of the REST API) to avoid fetching event data over the Internet. You still need to load the FullCalendar and Hebcal javascript files, but once they're loaded the page won't need to fetch additional data.

Try this approach to see if it improves your page speed?

https://gist.github.com/mjradwin/7145590367c8b88a194f8da5e9a8d325

To add a bit more detail,

תִּשְׁרֵי (transliterated Tishrei or Tishri) is the 7th month of the Hebrew year, is 30 days long, and corresponds to September or October on the Gregorian calendar.

The holiday that occurs on the 1st day of Tishrei is called Rosh Hashana, the Jewish New Year. Rosh Hashanah is a major holiday.

The first day of Tishrei is not considered Rosh Chodesh. Rosh Chodesh is a minor holiday that occurs at the beginning of every month on the Hebrew calendar. In the case of Tishrei, the major holiday of Rosh Hashana takes precedence.

Later in the month we observe Tzom Gedaliah on the 3rd, Yom Kippur on the 10th, Sukkot (from the 15th-21st), and Shmini Atzeret (on the 22nd) and Simchat Torah (on the 23rd in the Diaspora).

For more info, read The Month of Tishri – Judaism 101.