18-Minute Licht/Ner Shabbos

Why Does Shabbos ‘Start’ Eighteen Minutes Before Shekiah/Sundown?

December 2025

I. Forgetting the Frequent

    One of the saddest realities of our temporal existence is the temptation to take the common for granted.

  That newer friendship, those fresher experiences, or a novel skill will often garner the most attention – often at risk of overshadowing our more entrenched relationships and the more deeply-rooted elements of our lives.

   I have seen this play out in the high schools in which I teach. Should a new and talented student arrive and quickly find new friends, old loyalties often become jaded, feelings get hurt and, invariably, ‘drama’ ensues.

   The Ramban alludes to this phenomenon in a famous treatise (end of parshas bo).

   In a deeply complex exposition on the topic of nissim versus teva (miracles versus nature), Ramban teaches us something best aided with the following example: Consider a discarded apple seed that mindlessly stumbled from one’s mouth. Amazingly, the very soil at one’s feet will swallow that neglected matter, nurture it, until the ‘Calvin cycle’ commences the natural progression of photosynthesis. The sun, CO² , oxygen, water, and minerals work together as this tiny germ converts itself into energy. In time, that tiny crumb will flourish into a majestic apple-producing entity of its own.

   Is this all not a ‘miracle’, a ‘ness’? Why then do we relegate it, simply, to the grandiosity of nature?

Now consider how every one of these seeds contains a tiny ‘embryo’ for a new plant, as well as the nutrients to support that embryo (endosperm), and a coat to protect both. This ‘coat’ around each seed contains specific chemicals that signal if the embryo is in a safe environment to break free and develop or if it must stay as is, like when it’s in one’s hand.

 All of this is nothing less than dumbfounding!

To a man of faith, is this ‘nature’ or ‘miracle’?

More, why don’t we walk around in a state of shock regarding this and virtually every other aspect of chochmas haborei?

    This, Ramban explains, is due to teva’s sheer frequency, causing many to gloss over the fantastical ‘nature’ of yad Hashem around us. So that, on a surface level, the critical difference between a ness and teva is regularity.

 We simply often overlook that which we become accustomed to, that which is customary.

    Aside for explaining the distinction between ness and teva, and even beyond its underlying message regarding our friendships and loyalties, this often spills over into inyanei halacha.

II. Heligeh Shabbos

While balla batim will correctly encourage their rabbanim to spend significant time reviewing the halachos of Pesach, the kashrus of the daled minim, the dinnim for cholim, R”l, on Yom Kippur, and other seasonal issues, too often hilchos Shabbos can get left behind. This, although Shabbos is the holier than all other days save for Yom Kippur, a fact only known to us due to the Torah giving Yom Kippur the imprimatur of Shabbos (‘shabbos shabbason’)!

   Precisely because Shabbos is so constant, always coming back, returning again in six more days – come rain or shine – that we may subconsciously hit the snooze button on our desire and need to strengthen our relationship with it.

Chazal share a similar thought when explaining why Hashem shifted the length of an average human life after the mabul from several hundreds to into the hundredth year. When people lived for six, seven hundred years, they more easily procrastinate. “I will start doing the daf in a few hundred years”, “I have all the time in the world to improve”. This led to the many blunders committed in those epochs.

     Lahvdil, most of us consider yom tov seasons finite, thus forcing us to get it right, while subconsciously viewing Shabbos as infinite, full of ‘second chances’.

   As we start this winter, let us spend the next week or two discussing some fascinating shailos I’ve received recently that relate to Shabbos, and to all of us.

III. Long Shabbos, Short Shabbos, Early Shabbos  

It’s funny to consider the nickname many give to winter shabbosim -a ‘short Shabbos’- considering that Shabbos is obviously always going to be the exact same length of time each week!

   Of course, this moniker is simply referring to the the daytime, when we are awake and available to go for a walk, attend a shiur, etc. Summer provides long afternoons, while the winter rushes us from bentching to mincha. Hence, “short”.

   But what if I told you there was a way to make these “short shabbosim” longer? More, this is not just a method, but a full-fledged obligation!

    This is due to a halacha that everyone sort-of knows yet that is rarely taken out for deeper inspection.

The Shulchan Aruch twice mentions a halacha called tosefes Shabbos, of adding onto Shabbos, both at its start and its conclusion (261:2 and 293:1).

   This is not simply a nice thing to do, but, according to many, a Torah command (see Magen Avraham, Shulchan Aruch HaRav, etc.).

The earliest one can fulfill the halachic demand of tosefes Shabbos is at ‘plag hamincha’, which, depending on the deason, can equal anywhere from forty-five minutes to two hours before shekiah (sundown).

   As to the latest one can accept Shabbos and still fulfill tosefes Shabbos -there is some debate. While some seem to posit that even a few moments before shekiah is enough (see Aruch HaShulchan 261:2), most give a minimum of at least a couple of minutes before shekiah.

  So that what we in the summer colloquially call “An Early Shabbos” is, more literally, “An Earliest Possible Shabbos”. Meaning, this should not blind us to a weekly -yearly- obligation to take on each and every Shabbos at least a few minutes before shekiah.

   This halacha of tosefes Shabbos is the chief motivation behind the concept of ‘candle lighting times’ or ‘licht bencthing’. Have you wondered why there is a need for a special zeman for this lighting? The truth behind this zeman is that although one can fullfil the obligation to light candles right up until shekiah (although not recommended), we try to enforce tosefes Shabbos. Since women anyway accept Shabbos with their lighting, by creating this earlier time for them to light we thereby assure their tosefes Shabbos (see also Rema 256:1, with meforshim)!

While a woman may light past this time (before shekiah), it is a good guidepost to assure some tosefes was added to Shabbos.

   What about the men? Well, another obvious hint to this being a halacha is the fact that we introduce maariv with a special teffilah called…kabalas shabbos. The secret is in its name! Through this teffilah we can accept Shabbos on our own, early, and preferably before being forced upon us through sundown.

IV. 18 Minutes? Forty Minutes? Etc.

  Many questions remain.

For example, different communities established conflicting times to announce the start of Shabbos/licht. In parts of Yerushalaim, for example, the minhag is to announce and accept Shabbos/light about forty minutes before Shabbos (see shu”t Mishnas Yosef 4:33 for the history and its reasons behind this minhag), while other places in eretz yisroel do this at twenty minutes before shekiah.

  In most of America the minhag is to announce it at about eighteen minutes.

   Where did all these times come from? How does one (especially) men assure they accept Shabbos early in the winter, and what other minhagim were borne out of this halacha?

V. Zman Liche Bentching

Tosefes Shabbos is the chief motivation behind ‘candle lighting’ or ‘licht bencthing’ times we find in all calendars and zemanim charts. Those times are always set at some distance from shekia, varying in amount depending on minhag hamakom. Since women accept Shabbos with their lighting, creating this earlier time assures, at least for them, a tosefes Shabbos (see also Rema 256:1, with meforshim).

   Men too must accept Shabbos early, either through the teffila we name ‘kabalas Shabbos’ (for this reason!) or through a personal acceptance.

   We would be remiss not to make mention that this halacha applies both for going into Shabbos as well as coming out if it; in that one should wait some period of time after Shabbos is technically over before doing any melacha. (However, and depending on one’s city as well as personal minhag, the motzai Shabbos tosefes is often covered by the extra time we add before we declare it as being ‘ois Shabbos’).

VI. 18 Minutes & How Long Is Too Short?

Let’s start with when would be too early.

   The earliest possible time for tosefes Shabbos and for lighting neros Shabbos is plag hamincha (a season-dependent timeframe, which can be anywhere from forty-five minutes to two hours before shekiah).

  One who lights before plag should extinguish the candles and relight them at a proper time (Rema, 263:4).

   So that to tosefes can only be accomplished at some point between plag and shekia.

We mentioned above that in the Aruch HaShulchan’s view even if one accepts Shabbos a moment before shekia it would suffice for tosefes.

   Yet, this seems to be a minority opinion, as the views vary radically as to how long before shekia one would still fullfil their obligation of tosefes:

• One minute before shekia (Darchei Chaim V’Shalom, 2:364);
• Two minutes (shu”t Shvus Yaakov, 8:17;2; shu”t Eretz Tzvi, #60);
• Three minutes (Belz, al pi edus Rav Moshe Shternbuch, shu”t Teshuvos V’Hanhagos 3:83);
• Four minutes (shu”t Avnei Nezer, 2:498, et al.);
• Five minutes (Pichei Kehuna, siman 8);
• Between six and seven minutes (shu”t Maharshag, #38);
• Eight minutes (shu”t Toras Mordechai, 57:3)
• Ten minutes (Chut Hashani, shabbos, 4:84;1)
• Twelve minutes (Halichos Tzadikim, 1:p.322, note this is a different eidus of Belz than Rav Shternbuch’s three minutes. Although, in truth, Rav Shternbuch only mentions ‘three minutes’ regarding how long the rebbe would wait after Shabbos);
• Eighteen minutes (view of the Chasam Sofer, as reordered in Tzyana Malei Safra, p. 134)
• Thirty minutes (Arugos HaBosem (rishon), 1:p.224)
• Forty minutes (minhag Yerushalim, see shu”t Mishnas Yosef, 4:33, as well Tosefes Shabbos K’Hilchasa, p. 51 for the logic behind this lengthy tosefes; see also Dirshu to siman 262, #24)

In America we seemed to settle on ‘Eighteen minutes’, but we see from the above that even if someone missed that time-frame, their lighting or acceptance of Shabbos up until shekia may still accomplish tosefes.

  While I do not claim to know for sure the history behind our settling on eighteen minutes, we can share its possible preeminence.  

     In a separate mention of the chiyuv of tosefes Shabbos, the Shulchan Aruch writes, “…so long as one accepts Shabbos early at some amount of time when it is certain day” (261:2).  The Mishneh Berrura comments that this does not mean ‘even a moment’ before shekia, rather:

“A tiny addition to Shabbos would not suffice, as a little more is needed. The way to measure this would be that one’s hosafa [addition], added together with the length of bein hashmashos [until tzeis] would equal to about thirty minutes (ad loc. #22).

  If we can simply calculate how long shekia takes until tzeis, we can then easily subtract that time from the Chofetz Chaim total of thirty minutes to get to his number of minutes for tosefes!

Chazal teach that from sundown until tzeis takes the amount of time for one to walk three/fourths of a mil. Now, the measurement of time it takes to walk a full mil is seen throughout halacha -e.g. the time it takes for the chometz process to begin – and we generally take the position that this is equall to eighteen minutes.

   From there the math is simple: Three/fourths of a mil (3/4 of 18) would equal thirteen and a half minutes. Subtract that from the Mishneh Berrura’s total time of thirty minutes and we are left with about seventeen minutes for tosefes – sixteen and a half, to be exact.

   Rav Nissim Karelitz also makes this calculation to explain eighteen minutes (in the source above, in ha’ara).

  But wait! If that is the case, why not make the zman sixteen-and-a-half minutes, or round to seventeen minutes? How does this explain eighteen?

  While one may be tempted to suggest that this is to represent ‘chai’, this is not a check for a bar mitzvah! Not to belittle the koach of eighteen, but halacha would typically have more severe reasoning so as to infringe on people’s time!

    To explain this, we need to go back to the 12^th century. The great tosefis, Rav Eliezar of Metz (d.1198), argued the shekia does not begin when the sun goes beneath the horizon, rather it begins three/fourths of a mil (thirteen and a half minutes) before sundown!

   What does this view have to do with our minhag of eighteen minutes?   In a footnote to the above Mishneh Berrura (Shaar HaTion, #21) he reminds us that although we tend to calculate the full mil as equal to eighteen minutes, some poskim put it as high as twenty-four minutes. Meaning, even according to the strictest view of the time to walk a full (twenty four minutes) together with the severest view of when Shabbos actually should begin (three/fourths of that before sundown), tosefes would protect one from chillul Shabbos.

   Can the reader guess what three/fourths of twenty-four is?

That’s right…eighteen minutes!

   It would seem the Chofetz Chaim wanted us to make the sixteen and a half calculation, but then see his note, which would add another minutes and a half, to get to eighteen!

   To my surprise, Rav Moshe Feinstein rejects this as the source for our eighteen minutes candle lighting time (shu”t Igros Moshe 2:6).