Gregorian to Hebrew date converter
Enter a Gregorian date and get its Hebrew counterpart: 3 October 2024 is 1 Tishrei 5785. You also get the civil and the religious month number, and whether the year is a leap year with Adar I. Free in your browser.
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- Your data stays on your device
Run — free
Runs in your browser. Free, unlimited — your data never leaves this page.
This Gregorian to Hebrew date converter turns one explicit YYYY-MM-DD calendar date into the corresponding Hebrew year, civil month, religious month number, day, and readable date. It uses calendar arithmetic rather than a device clock, locale setting, or online lookup.
Enter an exact Gregorian calendar date
Provide a complete date in the form YYYY-MM-DD, including leading zeroes for the month and day. For example, 2024-10-03 is accepted, while 2024-10-3 and a natural-language phrase are rejected. The converter validates the date as a proleptic Gregorian calendar value, so century leap-year rules are applied correctly: years divisible by 400 are leap years, while other years divisible by 100 are not.
Impossible dates such as February 29 in a common year are rejected instead of being silently shifted. The supported Gregorian year range is 0001 through 9999. The input represents a civil calendar day, not a timestamp or a geographic observation of sunset.
Consequently, there is no time, offset, timezone, latitude, or longitude field to interpret. This makes the tool appropriate when a record already contains a definite Gregorian date and you need its arithmetic Hebrew-calendar counterpart. If your source event is a timestamp near sunset, first decide which local civil day your application intends to convert, because that domain decision cannot be inferred from a bare ISO date.
Understand the arithmetic Hebrew result
The calculation maps the Gregorian date to a fixed integer day and then locates that day within an arithmetic Hebrew year. Hebrew leap years follow the 19-year cycle, with seven leap years adding Adar I. The start of each year is determined with the traditional molad-based elapsed-day calculation and postponement rules.
Heshvan and Kislev then receive their appropriate lengths according to whether the year is deficient, regular, or complete. The response reports the Hebrew year, month name, day, and whether the year is a leap year. It also reports two month numbers because Hebrew months are commonly numbered in two useful ways.
The civil sequence begins with Tishrei as month 1, which is convenient for walking through a Hebrew civil year. The religious sequence assigns Nisan month 1 and Tishrei month 7; in a leap year, Adar I and Adar II are distinguished. Returning both conventions makes integrations explicit and avoids forcing a consumer to guess which numbering system a bare integer represents.
The readable field combines day, English month name, and year for straightforward display.
Use deterministic conversion responsibly
Every result is produced from the supplied string alone. The implementation does not call a network service, read the current clock, construct a JavaScript Date, use browser locale data, or select a timezone. For birth records, anniversaries, or observances whose Hebrew date depends on an event time after sunset, the conversion should be one step in a workflow that has already resolved the relevant local Gregorian day under the rules your organization follows.
Store the original ISO date beside the returned fields so later audits can reproduce the conversion and understand exactly what was supplied.
What you can do with it
Normalize archival records
Add explicit Hebrew calendar fields to records that already contain validated Gregorian ISO dates.
Build calendar interfaces
Display a Hebrew civil date beside a Gregorian date without relying on host locale or timezone behavior.
FAQ
Does the converter use my timezone?
No. It converts the explicit Gregorian calendar day you provide and does not read any timezone or device setting.
Why are there two Hebrew month numbers?
The civil numbering starts with Tishrei, while religious numbering starts with Nisan. Both are returned to remove ambiguity.
Does it handle Hebrew leap years?
Yes. It applies the 19-year cycle and returns Adar I and Adar II separately in leap years.
Can it decide whether an event after sunset belongs to the next Hebrew day?
No. A date alone contains no event time or location. Resolve the intended local civil day before conversion.
Which Gregorian dates are accepted?
Strict YYYY-MM-DD dates from 0001-01-01 through 9999-12-31, validated under proleptic Gregorian rules.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/date/gregorian-to-hebrew \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"date":"2024-10-03"}'const res = await fetch("https://api.kit.forhosting.com/date/gregorian-to-hebrew", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"date": "2024-10-03"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/date/gregorian-to-hebrew",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"date": "2024-10-03"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/date/gregorian-to-hebrew", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"date":"2024-10-03"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"date":"2024-10-03"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/date/gregorian-to-hebrew", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"date": "2024-10-03"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "date.gregorian_to_hebrew",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
year_min | 1 |
year_max | 9999 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Use deterministic conversion responsibly
The API price is $0.002 per request, while the browser execution can use the same pure logic without sending the date elsewhere. This capability implements the arithmetic Hebrew calendar, which is the standard deterministic basis for calculated calendar dates. It does not determine when a local sunset occurred, adjudicate historical observational calendars, or provide religious rulings.
Integration use cases
Create reproducible test data
Generate stable Gregorian-to-Hebrew fixtures for applications, migrations, and data-quality checks.
Technical questions
What does one conversion cost through the API?
One API request costs $0.002. The browser version runs the same deterministic logic locally.