Frequently Asked Questions

Scribal Art

What does "כסדרן" mean?

The text of mezuzah and tefillin scrolls must be written in the correct order. This means that a mistaken word or letter found in a completed scroll cannot simply be erased and then rewritten correctly, for then the corrected letter/word would be considered “out of order,” having been written after the subsequent text of the mezuzah or tefillin is already in place.

Now, if a mistake is found in the last line or two of the scroll, then all the words of these lines can be erased and then rewritten correctly, for in so doing the correct order of the entire text has been preserved. However, it is forbidden to erase the Name of G-d. Consequently, if the text of a scroll is found to contain any mistake prior to the last appearance of G-d’s Name – which occurs in the penultimate line of the text – then that mezuzah or tefillin scroll is irredeemably posul (invalid) and must be buried. Hours of work by the Sofer and parchment-maker have unfortunately gone to waste.

On account of this law, the Sofer is always very careful that before each time he writes the Name of G-d in a mezuzah or tefllin scroll, he meticulously checks for mistakes in all of the preceding words.

The law of “the correct order” does not apply to a Sefer Torah. In this respect, the laws concerning writing mezuzahs and tefillin are stricter than those concerning writing a Sefer Torah.

What is the purpose of the crowns (“tagin”) on some of the letters? Are mezuzahs or tefillin still kosher if those crowns have been omitted?

Tagin (“crowns”) extend from the top of the letter, and are comprised of three little lines, each of which is often shaped like the letter zayin. The tagin must be clearly written and may not touch any other letter.

The seven letters, shin, ayin, tess, nun, zayin, gimmel, tzaddy, are required to be written with tagin (crowns). Additionally, for a number of other letters the inclusion of tagin is considered “more optimal.” If tagin are omitted from any letter of either of these two categories, then the scroll is considered less than optimal.

If tagin have been omitted from a mezuzah or tefillin scroll, they may be added later. The reason that this later insertion of the tagin does not invalidate the scroll on account of being written “out of order” is because the basic form of the letter is already present.

The Talmud tells us that when Moses was on Mount Sinai, “he found the Holy One binding crowns for the letters.” He saw how many generations later, Rabbi Akiva, the great Rabbi of the Mishnah, would reveal the profound secrets of the tagin.

Nowadays, it is a very unfortunate fact that many unsuspecting consumers purchase mezuzahs and tefillin that are imperfect due to the omission of some or all of the necessary tagin.

Mezuzah Checking and Computer Scanning

What is the purpose of checking mezuzahs, and how often must it be done?

The purpose of checking mezuzah scrolls is to examine for defects and to inspect the present legibility of the text for deterioration that commonly occurs with time and/or adverse weather conditions, folding, or other factors.

While there is an opinion that recommends annual mezuzah checking, the widely accepted custom is to have one’s mezuzahs checked at least twice every seven years. Mezuzahs that experience greater exposure to inclement weather should be checked more often.

It should be noted that the checking process often results in preventive corrections that can increase the longevity of the mezuzah. For example, if a word is discovered in which the ink has slowly deteriorated (but the word is still legible), the deterioration can be “corrected” preventively – whereas if the ink would be left to be completely erased by the passage of time, the mezuzah would become irredeemably invalidated.

In addition to checking for initial mistakes and later deterioration, the infiltration of fraudulent mezuzahs in the marketplace presents further cause for checking mezuzahs.

Why do so many scribes and rabbanim encourage computer scanning of tefillin and mezuzahs?

The ability to perform computer scanning to check for errors in the text has facilitated a major advancement in the field of mezuzahs and tefillin. With computer scanning, the presence or absence of every word or letter is never overlooked. Moreover, the computerized database of the Vaad Mishmeret STaM has a record of every mezuzah and every tefillin scroll that was ever scanned into the system.

Utilization of the computer scanning method has brought serious instances of fraud to light. In one instance, the system identified several mezuzahs as being exactly identical, which would be impossible with handwritten parchments. Subsequent investigation revealed that the source was merely reproducing mezuzahs on parchment using a raised-ink printing process. In another instance, the system called attention to the fact that previously scanned mezuzahs with missing words or letters had been resubmitted with those errors corrected. Such parshios were thus defective as they were written she’lo k’sidran, out of order.

The Chicago Mezuzah Campaign raises awareness of the availability of computer-scanned mezuzahs and tefillin, and advises participants to purchase only mezuzahs or tefillin that have been written by certified sofrim and subsequently computer-scanned.

Affixing Mezuzahs

Where, exactly, is the mezuzah to be mounted?

mezuzah right side one thirdThe mezuzah is placed in a vertical position on the right-hand side of the door as one enters the room. The Ashkenazic custom is to affix the mezuzah on a slight angle, with the top of the mezuzah angled toward the inside of the room and the bottom angled toward the outside.

The mezuzah should be affixed in the lower part of the upper third of the doorpost. In most homes, the doors are approximately 78 inches high. Hence, the lowest permissible height should not exceed twenty-six inches from the top.

The mezuzah should not be placed lower than the upper third, nor should it be placed higher than four inches below the lintel.

A doorway that consists of two doorposts and a lintel that connects them requires a mezuzah. For doorways that do not meet these criteria, an observant Rabbi should be consulted to determine whether or not a mezuzah is still required.

What if my doorpost is very high?

If your door is much higher than 78 inches (90 inches or higher), many Rabbonim would instruct you to affix the mezuzah according to shoulder height, even though the shoulder-height may be lower than the upper third of the doorway.

Can I mount the mezuzah lower than the upper third of the doorpost, in order to enable my children to reach and kiss the mezuzah?


If a doorway can be utilized as an entrance from either side, how do I then determine what is considered the right (as opposed to left) side? What if I’m not sure if all my mezuzahs are affixed properly?

The laws defining the terms ‘entrance’ and ‘exit’ are multifarious and complex. It is therefore advisable to have a reliable observant Rabbi visit your home to make that determination. For a free home visit, you may call the CMC at 1-866 697-2224.

What if it’s physically impossible to affix the mezuzah on the doorpost itself (e.g. there is no space on the doorpost, or a swinging door is installed that interferes with the mezuzah)?

Since there’s no room on the doorpost itself, the mezuzah may be affixed on the outside of the doorpost.

In extenuating circumstances, such as the aforementioned examples, it would be preferred to carve out a groove, less than a handbreadth deep, into the doorpost and place the mezuzah into the groove. If that is not possible, then it would be permissible to affix the mezuzah behind the door, provided it is placed on the doorpost under the lintel.

This halacha also applies if one is genuinely concerned that the mezuzah will be stolen or defaced were it to be mounted on the actual doorpost.

If there is a stationary cabinet or the like in the doorway on the right side, where should the mezuzah be affixed?

Since the right side of this double-door is stationary, the Mezuzah is affixed on the end of the stationary door as shown, NOT on the doorpost all the way to the right.

The mezuzah should be affixed on the side of the cabinet, provided the cabinet is at least ten handbreadths high (approximately 32 inches). If the cabinet is lower than ten handbreadths high or if the mezuzah will not be secure in that position, then the mezuzah should be attached to the right doorpost.

Should I always affix my mezuzah at the horizontal center of my doorpost?

No. The mezuzah should be mounted on the outermost handbreadth (approximately 3.2 inches) from the outside of the doorpost. If the doorpost or archway is very wide, caution should be exercised not to mount the mezuzah in the center of the doorway. Use the above measurement to determine the proper placement of the mezuzah.

However, when there is a protrusion along the height of the doorpost, some Rabbonim would advise you to affix the mezuzah on the protrusion.

Am I obligated to use nails or screws to mount the mezuzahs?

No. You may also use glue or mounting tape. However, regular scotch tape or masking tape is not permitted.

What must I do with old mezuzah cases, old mezuzah wrappings or nails previously used for mezuzahs?

Nails, screws and tape that were used for mezuzahs may be discarded. However, mezuzah cases and mezuzah wrappings should be treated as “shaimos,” and thus require interment after their use.

Is there a problem with clear lucite cases?

It depends where the mezuzah will be placed. Lucite cases may not be used:

  • For a mezuzah that faces a bathroom.
  • On a doorpost or archway inside a bedroom door.
  • On any doorpost or archway of a room where diapers are changed.
  • In a laundry room.

Do all mezuzahs have to be returned to the same doorposts from which they were dismounted?

It is halachically preferable to have all of the mezuzahs returned to their original doorposts or at least to the same type of entrance way (e.g. from one bedroom door to another, or from one archway to another).

A practical suggestion for anyone removing his or her mezuzahs is to label each mezuzah case with a number (using masking tape or the like). The identical number is then taped on the doorpost itself. You must remember to request the scribe to replace all mezuzahs in their original cases. When remounting the mezuzahs, match the numbers from your cases to the numbers on the doorposts.

Is there a specific way of inserting the mezuzah in the case?

Yes, one needs to make certain that the scroll is inserted in the proper position. The “ש-ד-י-” must be facing the right way up, and positioned towards the “shin” of the mezuzah case. If necessary, tape should be used to keep the scroll in this exact position.

Who may affix mezuzahs on my behalf?

While others may affix the mezuzah on your behalf, this job may only be performed by a Jew above the age of Bar/Bas Mitzvah.

Please note that if you are having your home remodeled, it is important to ensure that non-Jewish workers do not remove and remount your mezuzahs.

May I affix mezuzahs at night?


When to Affix a Mezuzah

When purchasing a home, at what point does my obligation to mount mezuzahs begin?

The obligation to ensure that mezuzahs are mounted on a purchased home begins immediately upon moving in to the home. The blessing is recited at the time that the mezuzah is mounted.

When renting a home, when am I obligated to mount the mezuzahs?

When renting a home, you have a 30-day grace period (outside of Israel only) with regard to mounting mezuzahs. With regard to reciting a blessing on the mezuzahs it is actually preferable to wait until after the thirty days (the night of the 31st) before reciting the blessing. Therefore, some authorities suggest to wait until after the 30-day period before affixing any mezuzahs.

Others have the custom to affix all the mezuzahs immediately upon occupancy, without reciting the blessing. Subsequently, after the 30-day grace period has elapsed, one of the mounted mezuzahs (from a room that has a door) should be removed, checked and remounted. (That mezuzah may also be replaced with a new or upgraded one.) The proper blessing is then recited.

Others have the custom of affixing the mezuzahs with temporary tape immediately upon occupancy, and remounting them properly on the 31st day. The first mezuzah that is remounted properly should be on a room that definitely requires a bracha to be recited, and the bracha is recited at that time.

When do I begin counting the 30 days?

You should begin counting from the day you move in, or the day that you begin storing items in the house.

General Mezuzah Mounting

Which entrances are exempt from mezuzahs?

  • Bathrooms and shower rooms.
  • Storage rooms that are less than four cubits long and four cubits wide (approximately 6.4 ft. x 6.4 ft. or slightly less than 41 square feet).
  • A room with an area of sixteen square cubits, that has one side less than a cubit long. (e.g. 1’x 50’)
  • Any door that’s used only as an emergency exit.

Note that the doorway of a small room leading into a larger room (e.g. a foyer) requires a mezuzah. Furthermore, there are also other circumstances under which small rooms may require mezuzahs as well. Consequently, an observant Rabbi should be consulted to determine whether a mezuzah is required.

Does my home require mezuzahs while it is being renovated or painted?

Mezuzahs do not need to be mounted if this will interfere with the construction. However, a practical suggestion would be to use mounting tape to facilitate affixing or removing mezuzahs during construction.

A Word of Caution: When constructing a door in an archway that has a mezuzah of its own, the mezuzah must be removed before the door is installed. Subsequently, after the door is properly installed, the mezuzah should be remounted with a blessing. Never mount a mezuzah on a doorpost before the doorpost is installed.

What if I never use that door or if the door is blocked by furniture?

According to the majority of opinions, only unused doors that are sealed closed (e.g. the doors are actually nailed to the door frame) are exempt from mezuzahs. However, entrances blocked by furniture or doors that are usually kept locked require mezuzahs, as long as they are used at least once a year.

Do garage doors, boiler rooms, attics, outdoor sheds, or crawl spaces require mezuzahs?

According to many rabbinical authorities, mezuzahs are required on all garage doors (including garage overhead doors), boiler rooms, outdoor sheds, and even crawl spaces, provided that they comply with the required measurements (approximately 41 square feet).

At the entrance to a crawl space, the doorposts themselves must be at least 10 handbreadths high (approximately 32 inches) and four handbreadths wide.
An attic also requires a mezuzah, unless it has a horizontal doorway.

How do I appropriately measure square footage in a boiler room?

The measurement of 41 square feet should NOT include the space being used by permanently-mounted appliances or fixtures (e.g. boilers, cabinets). However, according to some opinions this space is indeed included in the measurement.

Are mezuzahs required on doors where refuse is stored?

No. The same will apply for any room whose permanent function involves the presence of a strong unpleasant odor.

Am I required to affix a mezuzah on a door leading to an empty room that is not being used at all?

Some authorities exempt such rooms from the placing of a mezuzah.

What about balconies or sun porches?

Balconies and porches require mezuzahs. In upper-floors, there is a difference of opinion whether the mezuzah is to be placed on the right side of the door leading into the house, or on the right side of the door leading onto the balcony (porch).

I live in a house with several sliding doors leading into the back yard. Should I affix mezuzahs in an identical way on all the sliding doors?

Not necessarily. It depends on whether the sliding door slides from right to left or from left to right. If the door slides from right to left (when facing the inside of your home), then the mezuzah is placed on the extreme right side as you enter the home. However, if the door slides from left to right (when facing the inside of your home), then you must affix the mezuzah on the right side of the doorpost, not on the extreme right side of the doorframe.

Do I need a mezuzah at my workplace?

Yes. In addition to private places of residence, mezuzahs must also be affixed (without reciting a blessing) in places of business and stores that are owned or rented by Jews. In the case that you’re working for a non-Jew and you are renting space from him, a mezuzah should be affixed (without reciting a blessing) on your office door. (Some authorities add that the obligation in this case applies only if one eats there as well.) However, if you work in an office or other space that you do not own or rent, and therefore the possibility always exists that your employer could relocate you without notice to a different space, then you would be exempt from affixing a mezuzah.

Am I obligated to affix a mezuzah on a room that is shared with another person?

If sharing with a Jew, it is an obligation upon each partner/tenant to affix the mezuzah. The opinions vary when sharing with a non-Jew. It is therefore recommended to put up a mezuzah without reciting a bracha, provided the non-Jew won’t mind and will allow you to put it up.

Is a landlord obligated to put mezuzahs in a building where not all the tenants are Jewish?

Keep in mind that in a rented home, the requirement to affix mezuzahs pertains to the tenant, not the landlord. Therefore, apartments that are rented to non-Jews (even if the owner is Jewish) are not required to have mezuzahs. Nevertheless, a Jewish landlord is required to affix mezuzahs on all the common areas of the building, as well as the vacant apartments that he uses.

I employ a maid who lives in my home. Am I required to affix a mezuzah on the door of her room?

Yes, providing that as part of the terms of her employment you have retained the right to change her room to another location in the house, at any given time and upon your discretion.

Does a washing room (outside a lavatory) require a mezuzah?

A mezuzah is required, providing that the washing room is at least 41 square feet and that there is another door separating the lavatory from the washing area.

Mezuzahs While Moving

If I am in the midst of moving and I temporarily own two homes, which one requires mezuzahs?

If you are actually living in both homes, or storing items in both homes, then you are obligated to have mezuzahs in both homes. We therefore recommend that you take advantage of the CMC’s mezuzah rental service. We will be happy to rent mezuzahs to you until you sell or rent your existing home. For more information, please call the CMC.

After moving to a new home, am I obligated to leave my mezuzahs up in the old home?

When moving to another house or apartment, mezuzahs should not be removed from the old home. The only exception to this rule is when either of the two following circumstances apply:

  • The new residents of one’s old home are not Jewish.
  • The old home does not have new residents yet, and there is concern that if the mezuzahs are left affixed to the doorways, there is a likelihood that they would become defaced.

May I remove my mezuzahs if the new Jewish residents have their own mezuzahs?

It is preferable that the new tenant or owner should remove your mezuzahs, or he should at least instruct you to remove your mezuzahs. This halacha is a very serious matter and should not be treated lightly. Rather, an observant Rabbi should instruct you what to do.

What if the new owner is Jewish and he wants mezuzahs, am I obligated to leave all of my mezuzahs behind?

Yes. However, you may exchange the mezuzahs for less expensive ones, providing that they are 100% kosher. The mezuzah cases may certainly be exchanged for the least expensive mezuzah covers.

You may also demand that the new owner or tenant pay you for the mezuzahs that you are leaving behind. He will then be obligated to compensate you for those mezuzahs at fair market value. If he refuses to pay for them, an observant Rabbi should be contacted. This halacha is a very serious matter.

What if I need mezuzahs for a second home while my house is under construction, or a second home used occasionally for vacationing?

If the second home is a rental, mezuzahs are required only if living there for more than thirty days. In the case of construction, we recommend that for that time period you avail yourself of the CMC’s mezuzah rental service. For more information, please contact the CMC.

Does a trailer, mobile home or a boat with living quarters require a mezuzah?

Yes. If you are renting them outside of the land of Israel, then you have the standard grace period of thirty days, whereas if they were purchased (or if the rental is in Israel), then mezuzahs should be affixed immediately following the sale. In any case, a blessing should not be recited when affixing these mezuzahs.

Does a car or a truck require a mezuzah?

Cars and trucks are exempt from mezuzahs. Some people choose to place a mezuzah in the car’s glove compartment for the purpose of “shmirah” (protection). It is permissible to do so, but one should be aware that this is neither a Torah nor a Rabbinical obligation.

Blessings for Mezuzahs

What is the blessing to be recited prior to affixing a mezuzah?

Prior to affixing a mezuzah upon a doorpost (that has a door), the following blessing should be recited:

ברוך אתה ה׳ אל־ה־ינו מלך העולם אשר קדשנו במצותיו וצונו לקבוע מזוזה

English transliteration: Baruch Ato A-do-nai Elo-heinu Melech ha-olam asher kideshanu b’mitzvotav v’tzivanu likboa mezuzah.

Translation: Blessed are You, L-rd our G-d, King of the universe, who has sanctified us with His commandments and commanded us to affix a mezuzah.

Even though one may be affixing many mezuzahs at one time, the text of the blessing remains the same, and is not changed to the plural (“likboa mezuzot”).

How many blessings do I make when I am affixing multiple mezuzahs in one building?

If the entire building belongs to one person, then only one blessing is recited when multiple mezuzahs are being affixed in the building at one time. After reciting the blessing, one should refrain from talking until all the mezuzahs are mounted.

However, if you will mount the mezuzahs on separate days, then a separate blessing should be recited each day before affixing the first mezuzah being mounted on that day.

Does the blessing “shehecheyanu” need to be recited?

No. The Ashkenazic custom is that the blessing “shehecheyanu” is never recited when affixing mezuzahs.

Are there any doors that require a mezuzah but do not require a blessing?

Yes. A blessing is not recited when affixing mezuzahs to:

  • Entrances of garages and storage rooms
  • Doorways or archways that have no actual doors
  • A room whose length is less than four cubits, but the total area is at least sixteen cubits square. (e.g. 4 x 10.5 feet or 3 x 14 feet)

In all of the aforementioned cases, one should try to affix mezuzahs to these entrances that do not require a blessing only after [reciting a blessing and] affixing a mezuzah to an entrance that does require a blessing.

The blessing on affixing a mezuzah is also not recited:

  • If the rooms are shared with a non-Jew
  • At one’s workplace

Do I recite a blessing when remounting the mezuzahs?

Recite the blessing only if the mezuzahs were off the doorposts for at least one night. If when you’re remounting the mezuzahs, you are also adding new mezuzahs, it is then preferable to recite the blessing on the new one (providing that it is mounted on a door that requires a blessing).

What if I drop a mezuzah on the floor, G-d forbid?

One who drops a mezuzah, G-d forbid, is not obligated to fast as in the case of a dropped Sefer Torah.

Am I required to recite a blessing when remounting a mezuzah after it falls off the doorpost?

Yes. This applies even in a case when the mezuzah is affixed immediately after it falls down.

What are the current-day equivalents to “handbreadths” and “cubits”?

It should be noted that there are a number of opinions regarding how to convert halachic measurements from their original form into modern-day equivalents. All halachic measurements in this publication follow the opinion of R’ Chaim Naeh. According to other opinions the measurements are longer and will therefore be a more lenient opinion in regards to the size of a room that requires a mezuzah.

However, it should be emphasized that according to all opinions there are many varieties of halachically stringent or lenient circumstances under which it is considered appropriate to calculate measurements using a somewhat more stringent or more lenient (as the case may call for) methodology. While the complexities of these details are beyond the scope of this publication, we hereby take the opportunity to point out that all the measurement values given herein are to be taken as approximate, not exact.

  • 10 handbreadths (‘TEFACHIM’) = approximately 80 centimeters (32 inches).
  • 4 cubits (“AMOT”) = approximately 192 centimeters (76.8 inches).
  • 4 square cubits = approximately 6.4ft. by 6.4ft.