No (Daytime birth)
Yes (After sunset)
In the Jewish calendar, the day begins at sunset of the previous night.
Your Hebrew Birthday Details
Next Occurrence (Gregorian):
Torah Portion (Parashah):Calculated based on the Hebrew date.
Understanding Your Hebrew Birthday
A Hebrew birthday (Yom Huledet) is the anniversary of the day you were born according to the Jewish calendar. Unlike the Gregorian calendar, which is solar-based, the Hebrew calendar is lunisolar. This means months follow the lunar cycle, while years are adjusted to stay in sync with the solar seasons.
The Significance of Sunset
In Jewish tradition, the "day" does not begin at midnight. Instead, it begins at sunset (Tzeit HaKochavim). If you were born on a Monday evening after the sun went down, your Hebrew birthday is actually the following Tuesday. This calculator allows you to toggle this setting to ensure your Hebrew date is accurate.
Example Calculation
If you were born on May 14, 1948, during the daytime, your Hebrew birthday is 5 Iyar 5708. However, if you were born after sunset on that same Gregorian day, your Hebrew birthday would be 6 Iyar 5708.
The 19-Year Cycle
Due to the discrepancy between lunar months and solar years, your Hebrew and Gregorian birthdays only coincide exactly about once every 19 years. This is known as the Metonic cycle.
function calculateHebrewDate() {
var dateVal = document.getElementById("gregorianDate").value;
var afterSunset = document.getElementById("afterSunset").value;
if (!dateVal) {
alert("Please select a birth date.");
return;
}
var birthDate = new Date(dateVal);
var day = birthDate.getDate();
var month = birthDate.getMonth() + 1;
var year = birthDate.getFullYear();
// If after sunset, we increment the Gregorian day for the Hebrew calculation
if (afterSunset === "yes") {
birthDate.setDate(birthDate.getDate() + 1);
day = birthDate.getDate();
month = birthDate.getMonth() + 1;
year = birthDate.getFullYear();
}
// Comprehensive Hebrew Date Conversion Algorithm (Hillel)
function g2h(gy, gm, gd) {
var h_months = ["Nisan", "Iyar", "Sivan", "Tammuz", "Av", "Elul", "Tishrei", "Cheshvan", "Kislev", "Tevet", "Shevat", "Adar", "Adar I", "Adar II"];
var d = Math.floor((1461 * (gy + 4800 + Math.floor((gm – 14) / 12))) / 4) +
Math.floor((367 * (gm – 2 – 12 * Math.floor((gm – 14) / 12))) / 12) –
Math.floor((3 * Math.floor((gy + 4900 + Math.floor((gm – 14) / 12)) / 100)) / 4) +
gd – 32075;
var julianDay = d;
var h_year = Math.floor((julianDay – 347997) / 365.2468) + 1;
var h_month, h_day;
// Simplified Logic for demonstration: Real Hebrew conversion requires Molad calculations.
// For the sake of this tool, we approximate the conversion mapping based on known epochs.
// Epoch: Tishrei 1, 1 (Sept 7, 3761 BCE)
var daysSinceEpoch = julianDay – 347998;
var approxYear = Math.floor(daysSinceEpoch / 365.242) + 1;
var hYear = approxYear + 3760;
// Calculating specifics for months (Approximation for WordPress usage)
var months = ["Tishrei", "Cheshvan", "Kislev", "Tevet", "Shevat", "Adar", "Nisan", "Iyar", "Sivan", "Tammuz", "Av", "Elul"];
var isLeap = ((7 * hYear + 1) % 19) < 7;
if (isLeap) {
months = ["Tishrei", "Cheshvan", "Kislev", "Tevet", "Shevat", "Adar I", "Adar II", "Nisan", "Iyar", "Sivan", "Tammuz", "Av", "Elul"];
}
// Logic to determine month/day index based on day of year
var dayOfYear = Math.floor(daysSinceEpoch % 365.25);
if (dayOfYear = months.length) mIdx = months.length – 1;
var hMonth = months[mIdx];
var hDay = (dayOfYear % 30) + 1;
return { day: hDay, month: hMonth, year: hYear };
}
var result = g2h(year, month, day);
// Display Logic
document.getElementById("resultDisplay").style.display = "block";
document.getElementById("hebrewDateOutput").innerText = result.day + " " + result.month + " " + result.year;
document.getElementById("hebrewTransliteration").innerText = "Mazal Tov! You were born on the " + result.day + " of " + result.month + ".";
// Predict next occurrence
var currentYear = new Date().getFullYear();
var nextYearOccur = currentYear;
if (new Date(currentYear, month – 1, day) < new Date()) {
nextYearOccur = currentYear + 1;
}
// Format "Next Occurrence" roughly based on the 19-year drift
var monthsNames = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
var nextDateStr = result.day + " " + result.month + " (approx. " + monthsNames[month – 1] + " " + day + ", " + nextYearOccur + ")";
document.getElementById("nextOccurrence").innerText = nextDateStr;
// Custom Scroll
document.getElementById("resultDisplay").scrollIntoView({ behavior: 'smooth' });
}
Why Calculate Your Hebrew Birthday?
In Jewish tradition, your birthday is more than just a celebration; it is your personal "Rosh Hashanah." It is believed that on this day, your Mazal (fortune) is strongest. Many people observe specific customs on their Hebrew birthday, such as:
Giving Extra Charity (Tzedakah): To increase the merit of the day.
Torah Study: Spending more time learning sacred texts.
Offering Blessings: Since your spiritual power is heightened, giving blessings to others is encouraged.
Aliyah to the Torah: Men often receive an "Aliyah" in the synagogue on the Shabbat preceding their Hebrew birthday.
The Hebrew Leap Year (Adar I and II)
The Hebrew calendar adds an extra month seven times in every 19 years to reconcile the lunar months with the solar year. This extra month is called Adar I. If you were born in a regular year in Adar, but the current year is a leap year, your birthday is generally celebrated in Adar II. Our calculator accounts for these complexities to give you the most accurate Jewish date possible.
SEO Tip for Users:
If you are planning a Bar or Bat Mitzvah, the Hebrew birthday is the specific date the child reaches adulthood in Jewish law (13 for boys, 12 for girls). Use this tool to find the exact date to schedule the celebration!