Shabbat Times

Why light Shabbat candles 18 minutes before sunset?

Shabbat officially starts at sunset. So why does every Jewish calendar tell you to light candles 18 minutes before? There are a few good reasons, some practical and some rooted in the Talmud.

Updated September 29, 2026 · Based on sources from Chabad.org

Adding to Shabbat

Jewish law asks us to start Shabbat a little early and end it a little late. It's called tosefet Shabbat, "adding to Shabbat." The Talmud learns it from the way the Torah describes Yom Kippur, and most authorities hold it's a Torah-level idea: we don't squeeze Shabbat into the minimum, we give it extra room. Lighting before sunset is how that extra time begins.

A safety margin

There's a practical side too. Once Shabbat begins, lighting a fire isn't allowed. Clocks can be off, the sunset time is an estimate, and Friday afternoons get busy. Lighting 18 minutes early builds in a cushion so no one accidentally lights after Shabbat has already started.

Why 18 minutes exactly?

Two classic explanations are given:

Why is Jerusalem 40 minutes?

The 18-minute time is the custom in most places, but not all. Jerusalem has a long-standing custom of lighting 40 minutes before sunset, and some other communities use 20, 22 or 30 minutes. These are local customs, and all of them come from the same idea of adding time to Shabbat. Shabbat Times uses 40 minutes for Jerusalem automatically, and you can change the number of minutes in settings to match your community.

Earliest and latest times

Latest: if you've missed the 18-minute time, you can still light right up until sunset, but not after. Earliest: you can light and start Shabbat early, which many families do on long summer Fridays, but no earlier than plag hamincha, about an hour and a quarter (in halachic hours) before sunset.

Find this Friday's exact time on the Shabbat Times home page.

Common questions

Why do we light Shabbat candles 18 minutes before sunset?

To add time to Shabbat (tosefet Shabbat) and to leave a safety margin so the candles are never lit after Shabbat begins. The number 18 comes from Talmudic calculations of the time it takes to walk a mil.

Can I light Shabbat candles after the 18-minute time?

Yes, you can still light until sunset. After sunset it's too late.

How early can I light Shabbat candles?

No earlier than plag hamincha, about an hour and a quarter (in halachic hours) before sunset.

Why is candle lighting 40 minutes before sunset in Jerusalem?

It's a long-standing local custom in Jerusalem. Other communities use 18, 20, 22 or 30 minutes; all are based on adding time to Shabbat.

Sources