How to Tell if a Mezuzah is Kosher: Signs to Look For

Knowing how to tell if a mezuzah is kosher is one of the most important responsibilities a Jewish homeowner carries. The mezuzah on your doorpost is not a decoration, and it is not merely a cultural symbol. It is a mitzvah (Torah commandment) whose proper fulfillment depends entirely on the integrity of the scroll inside. A beautiful case means nothing if the klaf (parchment) within it is pasul (invalid). If you want to fulfill this mitzvah properly, you need to know what makes a mezuzah scroll kosher, and what signs tell you it may not be.

If you have questions about a specific scroll you own or are considering purchasing, you are welcome to reach out to us directly for guidance rooted in halacha and decades of experience with verified, OU-certified mezuzah scrolls.

How to Tell if a Mezuzah is Kosher: Signs to Look For

What Makes a Mezuzah Scroll Kosher

A mezuzah scroll is kosher when it meets the full requirements of halacha (Jewish law) as codified in the Shulchan Aruch (Yoreh De'ah, Siman 288) and the major Poskim (halachic authorities). The scroll must be handwritten by a qualified sofer (scribe) on kosher klaf (parchment) made from the hide of a kosher animal, using kosher dio (ink). Every letter must be formed correctly, every word must be spelled accurately, and the text of the two parshiyos, Shema (Devarim 6:4–9) and Ve'haya Im Shamoa (Devarim 11:13–21), must be written in the proper order. If any single letter is missing, cracked, or malformed to the point that its tzurat ha'ot (letter form) is compromised, the entire mezuzah may be rendered pasul (invalid).

The obligation to affix a mezuzah is not simply an act of placing text on a doorpost. The Rishonim and Acharonim explain that the mezuzah functions as a form of kahal (public declaration) of the Oneness of Hashem within the home itself, parallel in concept to Kriyat Shema (the recitation of Shema), which is the declaration of that same Oneness in speech. Just as Kriyat Shema must be recited correctly, word by word, letter by letter, so too the mezuzah must be written with that same standard of precision. The Rambam (Hilchos Mezuzah 1:1) makes clear that a mezuzah written improperly, even if the text is present, does not fulfill the mitzvah.

For a practical overview of halachic requirements before purchasing or verifying a scroll, our comprehensive guide to kosher mezuzah placement, styles, and buying is a helpful place to begin.

The Halachic Standards That Determine Kosher Status

The halachic framework for determining whether a mezuzah is kosher rests on several distinct requirements, each of which has its own body of responsa and rulings.

The klaf (parchment) must be made specifically for the purpose of writing a mezuzah. The Shulchan Aruch (Yoreh De'ah 288:6) rules that klaf prepared without the proper lishmah (intent for the sake of the mitzvah) is invalid. This means the person who processed the parchment must have had in mind that it is designated for sacred writing. This is not something a buyer can verify by looking at the scroll alone, it requires trust in a certified, reputable sofer and a proper chain of verification.

The dio (ink) must be black, durable, and applied to the surface of the klaf rather than absorbed into it. The Gemara (Gittin 19a) and the Shulchan Aruch both address the standards for ink used in sacred writing. Ink that fades, flakes, or cracks over time can compromise the tzurat ha'ot (form of the letters), which in turn can render the mezuzah pasul. This is why regular checking, bedikah, is required by halacha, as codified in the Shulchan Aruch (Yoreh De'ah 291:1): a mezuzah in a private home must be checked twice in seven years.

The sirtut (scoring lines) on the klaf serve as a writing guide for the sofer and are halachically required, as the Shulchan Aruch (Yoreh De'ah 288:8) rules. A scroll written without sirtut is pasul. You cannot see the sirtut clearly from outside the case: a magiah (inspector) trained in STAM (Sifrei Torah, Tefillin, and Mezuzos) must examine the scroll directly. The Chatam Sofer affirmed that any person, not only a trained sofer, may inspect a mezuzah to check whether letters have rotted or faded, but a trained magiah is required to evaluate issues of letter form and other technical invalidations.

The writing must also proceed in order, Shema before Ve'haya Im Shamoa. The Taz (Yoreh De'ah 289) notes that if the parshiyos are reversed or written out of sequence, the mezuzah is pasul. This is not merely a formal requirement: it reflects the principle that the mezuzah serves as the "Shema of the house," and just as the Shema must be recited in order, the mezuzah must be written in order.

How to Verify a Mezuzah in Practice

Verifying a mezuzah scroll properly requires more than a visual inspection. There are, but, several signs that a knowledgeable person can look for, and there are steps you can take to ensure the mezuzah you own or are purchasing is genuinely kosher.

When examining a mezuzah scroll you already own, the first thing to check is whether the scroll is handwritten or printed. A printed mezuzah, regardless of how authentic it appears, is pasul according to all opinions and does not fulfill the mitzvah under any circumstances. Printed scrolls are mass-produced and have no sofer, no klaf processed lishmah, and no halachic validity. Unfortunately, printed scrolls are sold commercially in many non-specialized stores, and some buyers are unaware of the difference. If the letters look perfectly uniform and machine-like, or if the scroll is very inexpensive, that is a warning sign.

Second, look at whether there is a certified magiah (inspector) who examined the scroll and a named sofer who wrote it. A kosher mezuzah should be traceable, you should know who wrote it, who checked it, and when it was last inspected. Kosher Mezuzah Company is dedicated to ensuring the proper fulfillment of the mitzvah of mezuzah, which is why every scroll we provide comes with verifiable information about the sofer and the magiah, certified through the Orthodox Union. To learn more about how that certification process works, see why the OU endorses Kosher Mezuzah and what that means for the validity of your scroll.

Third, check whether the mezuzah has been inspected recently. Even a mezuzah that was once kosher can become pasul over time due to environmental exposure, heat, moisture, and insects can damage the klaf and the ink. Halacha requires that you check your mezuzos regularly. If you do not know when your mezuzah was last inspected, that alone is reason to have it checked.

Practical Steps for Verifying a Mezuzah

1. Remove the scroll from its case carefully and examine whether the writing appears handwritten, with natural variation in letter size and spacing. If it looks printed, it is invalid.
2. Look at the back of the klaf for the word "Shaddai" (a name of Hashem), which must be written by the sofer. If it is absent or printed, that is a problem.
3. Check whether there is a certification or accompanying documentation naming the sofer, the magiah, and the date of writing or inspection.
4. If there is a QR code on the case or documentation, scan it, modern verification systems allow you to see the specific scroll's details, as explained in our article on what a QR code on your mezuzah tells you.
5. If you cannot verify the above, bring the scroll to a qualified magiah or contact a reputable source such as Kosher Mezuzah for a professional evaluation.

For a broader foundation of knowledge about what to look for and why it matters, the Kosher Mezuzah learning center provides detailed, halachically grounded explanations.

Common Mistakes When Trying to Verify a Mezuzah

One of the most widespread mistakes is assuming that a mezuzah in a Jewish store is automatically kosher. This is not always the case. Some commercial retailers carry scrolls that are printed, improperly certified, or written by scribes who do not meet the required halachic standards. The fact that a scroll is sold in a Judaica shop or labeled "kosher" on its packaging does not substitute for actual verification by a qualified authority. As the risks of purchasing a mezuzah on Amazon illustrate clearly, the marketplace for mezuzah scrolls includes many sellers who are not equipped to guarantee halachic validity.

A second common mistake is relying solely on visual appearance as a sign of kashrus (kosher status). A scroll can look beautiful, with elegant script, even spacing, and a lovely case, and still be pasul. Conversely, a scroll that looks simple and unadorned may be entirely mehudar (enhanced in quality). The kashrus of a mezuzah depends on internal halachic criteria that cannot be assessed from the outside. The tzurat ha'ot, the condition of the klaf, the kashrus of the ink, and the sequence of the parshiyos all require trained examination.

A third mistake is neglecting to have mezuzos checked after life changes such as moving into a new home, returning from a long period away, or after unusual environmental exposure. The Pithchei Teshuva brings that even if three mezuzos were checked and found valid, all must still be checked, you may not stop midway and assume the rest are fine. Delaying bedikah (checking) is a real halachic problem, not a chumra (stringency) for the especially pious.

The Spiritual Significance of Knowing Your Mezuzah is Kosher

The mitzvah of mezuzah is not just a matter of legal compliance. The Rambam (Hilchos Mezuzah 6:13) writes that one who is careful in the mitzvah of mezuzah will be protected, and Chazal (our Sages) in the Gemara (Shabbat 23b) teach: "One who is careful with mezuzah merits a beautiful dwelling." The Gemara in Avodah Zarah (11a) recounts how Onkelos the Convert explained to the Roman emperor's servants that while a human king sits inside while his guards protect him from without, Hashem's servants dwell inside and He guards them from without, as the pasuk (Tehillim 121:8) states, "Hashem shall guard your going out and your coming in, from now until eternity."

This protection and this zechus (merit) are contingent on the mezuzah being truly kosher. A pasul mezuzah hanging on a doorpost does not fulfill the mitzvah, and hence does not carry the same spiritual significance as one that was written, inspected, and affixed properly. The Lubavitcher Rebbe zt"l, in his worldwide mezuzah campaign of 1974, stressed that the protective quality of the mezuzah is dependent on the mezuzos being kosher and affixed in strict accordance with halacha. The mitzvah is precious precisely because of its precision.

The mezuzah is, in the words drawn from the deeper halachic sources, the "Shema of the house", a continuous written declaration of Hashem's Oneness fixed permanently at the entrance of the Jewish home. Your mezuzah should be a reminder of holiness and protection for your home, and that reminder is only meaningful when the scroll within it is genuinely kosher.

What to Do Next to Ensure Your Mezuzah Is Truly Kosher

A mezuzah is kosher when it is handwritten on valid klaf by a qualified sofer, written lishmah in the correct order with proper sirtut, certified by a trained magiah, and checked regularly according to halachic intervals. Visual appearance alone cannot tell you whether your mezuzah meets these standards. The only reliable way to know is through proper verification, by obtaining a scroll with traceable documentation, by having existing scrolls inspected by a qualified magiah, and by purchasing only from sources whose certification and standards you can confirm.

Kosher Mezuzah ensures each mezuzah scroll meets the highest halachic standards, with full traceability from the sofer's writing to the magiah's inspection, backed by certification from the Orthodox Union, the most trusted kosher certification authority in the United States. If you have questions about your current mezuzos or are ready to obtain a verified, kosher scroll, our full FAQ on kosher mezuzah standards addresses the most common concerns clearly and practically. Consult your rabbi for any specific halachic questions about your home or circumstances, and never hesitate to seek guidance when there is doubt.

To take the next step in fulfilling this mitzvah properly, you are welcome to browse our selection of OU-certified mezuzah scrolls and find the right scroll for your home and community's minhag (custom).

May the mitzvah of mezuzah bring blessings and protection to your home.

Frequently Asked Questions: How to Tell if a Mezuzah Is Kosher

How can I tell if a mezuzah scroll is handwritten or printed?

Look closely at the letters — a handwritten mezuzah will show natural variation in size, spacing, and ink density. Printed scrolls appear perfectly uniform and machine-like. A printed mezuzah is pasul (invalid) under all halachic opinions and does not fulfill the mitzvah, regardless of how authentic it looks.

What makes a mezuzah scroll kosher according to halacha?

A kosher mezuzah must be handwritten by a qualified sofer on parchment (klaf) processed lishmah, using kosher black ink, with required scoring lines (sirtut), every letter correctly formed, and the two Torah portions written in the proper order. Any single compromised letter can render the entire scroll pasul (invalid).

How often does a mezuzah need to be checked to remain kosher?

Halacha (Shulchan Aruch, Yoreh De'ah 291:1) requires a mezuzah in a private home to be checked twice in seven years. Even if some mezuzos are found valid, all must still be inspected — you cannot assume the unchecked ones are fine. Environmental factors like heat, moisture, and insects can damage the klaf and ink over time.

Can I verify a mezuzah's kosher status myself, or do I need a professional?

You can perform basic checks — confirming handwriting, locating the word 'Shaddai' on the back, and reviewing sofer and magiah documentation. However, evaluating letter form (tzurat ha'ot), ink condition, and sirtut requires a trained magiah (inspector). For full verification, always consult a certified professional or a reputable source.

Is a mezuzah sold in a Jewish store automatically kosher?

Not necessarily. Some Judaica retailers stock printed, improperly certified, or substandard scrolls. A 'kosher' label on packaging is not a substitute for verification by a qualified halachic authority. Always confirm the sofer's identity, the magiah's certification, and the certifying body — such as the Orthodox Union — before trusting any scroll's validity.

Why does a pasul (invalid) mezuzah not carry the same spiritual protection as a kosher one?

The Rambam (Hilchos Mezuzah 6:13) and Chazal teach that the mitzvah's protective quality is contingent on the mezuzah being genuinely kosher and properly affixed. The Lubavitcher Rebbe stressed this during his 1974 worldwide mezuzah campaign. A pasul mezuzah does not fulfill the mitzvah and therefore does not carry the same spiritual significance or merit.