What's my Jewish zodiac sign? — your Hebrew birthday, computed

Your mazal follows the Hebrew month you were born in — which usually is not the month your Western sun sign suggests. Enter your birth date; the classical conversion runs right here, nothing leaves your browser.

The Hebrew calendar is lunisolar: months follow the moon, years are pinned to the seasons with leap months. Against the fixed Gregorian grid, everything drifts — so the Western sign windows (March 21 – April 19 and the rest) slice across two Hebrew months each, differently every year. Two people who share a sun sign routinely carry different mazalot. The mazal, in turn, comes with a tribe, a letter, and one of the twelve senses of Sefer Yetzirah ch. 5 — a fuller anatomy than a sun sign, and in the tradition's own words, never a verdict: ein mazal l'Yisrael.

Hebrew vs Western: two different calculations

Short answer: your Western sign comes from the sun's position on a fixed Gregorian date; your Jewish sign (mazal) comes from the Hebrew month you were born in. The Hebrew month begins at the new moon and slides about eleven days against the civil calendar every year, so the same civil date can fall in different Hebrew months in different years. Each Western date window therefore overlaps two Hebrew months, and roughly a third of people land in a different sign under the Hebrew reckoning.

The order of the wheel is the same — Nisan opens with the Ram, Adar closes with the Fishes (Sefer Yetzirah ch. 5 pairs each month with its constellation, a letter, a tribe and a human faculty) — but the boundaries are the moon's, not the sun's. That is the whole of the difference, and it is why the calculator above converts your date before it names a sign. Why the two signs differ, in full →

Checked examples

Conversions computed with the @hebcal/core calendar library (checked 5 September 2026). "After sunset" rows use the next Hebrew day; the exact sunset minute depends on the birthplace, which is why the calculator asks for it.

Born after sunset

The Jewish day runs from nightfall to nightfall. A birth at 9 p.m. on the 1st belongs to the Hebrew date that begins that evening — one day later than a daytime conversion gives. Tick "I was born after sunset" above and the calculator moves you to the next Hebrew day. In most cases only the day number changes; the month, and so the mazal, changes only when you were born on the evening that ends a month. Between sunset and full dark (bein hashmashot) the day is genuinely in doubt; the honest answer there is "one of two dates", and the classical discussion of birth hour is at Shabbat 156a.

If you do not know your birth time

Leave the sunset box unticked and use the daytime result; that is correct for roughly two thirds of births. If you later find the hour on a birth certificate and it is after sunset, re-run with the box ticked. On the full reading, choose "I don't know my birth time" — the reading uses noon, the month and mazal stay the same, and only the planetary-hour layer (which needs the hour) is read more cautiously.

Leap years and the two Adars

Seven years in nineteen add a second Adar so the lunar months keep pace with the seasons (the reckoning debated at Rosh Hashanah 10b). A birth in Adar I or Adar II is still Adar — mazal Dagim (Pisces). The calculator shows which Adar you were born in; the month page covers what custom does with it. The founding instruction for the whole system is Exodus 12:2, and Genesis 1:14 is where the lights are given "for signs and for seasons".

Our reading: what a mazal says about temperament is interpretation built on these sources, offered for reflection. The tradition's own limit — ein mazal l'Yisrael, there is no decree for Israel — stands over every line of it.