Deadbolt Grades: How ANSI/BHMA Ratings Really Work

Why deadbolt grades confuse almost everyone

A lot of buying advice still says deadbolts are graded 1, 2 or 3 and then quotes cycle counts for each. That picture is out of date for home locks, and the cycle counts usually come from a different standard.

Here is the short version. Since 2015, residential deadbolts have had their own standard, ANSI/BHMA A156.40, which rates each lock with letters, not numbers. The familiar Grade 1, 2 and 3 for deadbolts comes from A156.36, the auxiliary lock standard. A good residential deadbolt often carries both, which is why the box can look contradictory.

BHMA (the Builders Hardware Manufacturers Association) publishes the ANSI/BHMA standards and runs the certification program. Below, every number comes from BHMA's own public summaries or from manufacturer pages, and where BHMA does not publish a number, we say so.

Scale one: A156.40 letter ratings

A156.40, Residential Deadbolts, was approved on January 15, 2015. It and A156.39 for residential locksets were BHMA's first standards written specifically for homes. The current edition is A156.40-2025.

Instead of one overall grade, the lock is rated A, B or C in three separate categories:

• Security (BHMA groups strength and security together)
• Durability
• Finish

The lock has to pass every test for its grade in each category on its own. On BHMA's residential label, C means good, B means better and A means best. So "AAA" is shorthand for an A in all three, and a lock could, for example, rate A for security but lower for finish.

Scale two: A156.36 Grade 1, 2 and 3

A156.36 covers auxiliary locks. Schlage's training material uses that term for deadbolts: locks whose bolt only moves when someone deliberately turns it. The edition BHMA lists is A156.36-2020, and it includes operational, cycle, strength, security and finish tests.

This is the standard behind most "Grade 1 deadbolt" claims. Commercial deadbolts such as Schlage's B600 series are rated to it, and so are many residential models that also carry an A156.40 rating.

What the top deadbolt grades require

BHMA's public summaries describe only the highest level of each standard. Here is what they say, side by side.

Two things stand out. The top residential letter calls for more cycles and more security tests than A156.36 Grade 1, so "Grade 1" is not automatically the stronger claim. And both include the same 1,350 lb door force test at the top level.

Still, these are different standards with their own procedures, so the table is a guide to what each one covers, not a head-to-head score.

The missing numbers for Grade 2, Grade 3, B and C

The full standards are paywalled, and the free summaries stop at the top grade. If an article gives exact cycle counts for Grade 2 and Grade 3 deadbolts, ask where they came from.

Often the answer is a different lock type entirely. Allegion's 2013 guide to BHMA grading has a widely shared cycle table, and it covers bored locks and mortise locks, not deadbolts. We reproduce it below with that label, because it explains where the familiar "1,000,000 / 400,000 / 200,000" figures originate.

Editions have changed since 2013. Use this table to recognize borrowed numbers, not to judge a deadbolt.

BHMA's A156.40 summary notes that the Certified Products Directory lists the test requirements for certified residential products. That directory, not a blog post, is the place to look for the detail behind a B or C.

How to read the rating on a deadbolt box

Manufacturers print the rating as a single spec line, and it packs in more than it seems. Schlage's B60 single cylinder deadbolt is a clean example: it lists "ANSI/BHMA A156.40-2015 Grade AAA in Security, Durability and Finish" and also "ANSI/BHMA A156.36-2010 Grade 1."

Text version of this diagram

1. A156.40: the ANSI/BHMA standard for residential deadbolts.

2. -2015: the edition the lock was tested to. The current edition is 2025.

3. AAA: one letter each for security, durability and finish. A is best, B is better, C is good, and each letter is earned separately.

4. A156.36: the ANSI/BHMA standard for auxiliary locks, which includes deadbolts.

5. Grade 1: the top of the A156.36 scale of 1, 2 and 3.

Then verify the listing in BHMA's Certified Products Directory, searching by brand or standard.

Not every box looks like that. Kwikset's 660 deadbolt spec sheet lists ANSI/BHMA A156.2 Grade 3, a rating under the locks and latches standard rather than either deadbolt standard. When two boxes cite different standards, you are not comparing like with like.

Commercial models add another twist. Schlage rates its B600 deadbolt Grade 1 with a conventional cylinder, Grade 2 with a full-size interchangeable core and Grade 3 with a small-format interchangeable core. The cylinder option you order can change the grade.

A grade with no standard number attached tells you much less. "Grade 1" alone could refer to several different BHMA standards.

Checking a lock in BHMA's Certified Products Directory

BHMA's Certified Products Directory lists every product certified to its standards. Certification relies on tests verified by independent third-party labs, with periodic recertification, and anyone can search it. Allegion's guide adds that certified products are audited through random samples.

1. 01

   Copy the spec line

   Note the brand, model number, standard and rating exactly as printed.

2. 02

   Open the directory

   Go to the Certified Products Directory on buildershardware.com.

3. 03

   Search

   Search by brand, or by standard such as A156.40 or A156.36.

4. 04

   Match the model

   Find the same model and compare the listed rating with the box.

5. 05

   Ask if missing

   If the model is not listed, ask the manufacturer which certification it holds.

Deadbolt grades vs UL 437 and the commercial standards

BHMA grades judge the whole lock. Other ratings judge one part of it, or a different kind of lock, and they show up on the same shelves.

UL 437 is a cylinder listing, so it sits on top of a grade rather than replacing it. Schlage's B600 is A156.36 Grade 1, but it is UL 437 listed only when fitted with a Primus UL 437 cylinder. If key control and drill resistance matter for your door, read how a UL 437 high security deadbolt is put together.

The A156.13 mortise standard matters mostly for businesses. Its Grade 1 includes a 1,200 in-lbf locked-lever torque test, which applies to the lever hardware that mortise locks carry. We cover mortise and storefront hardware on our page about deadbolts for business doors.

Grades on smart and keypad deadbolts

Electronics do not exempt a lock from the standards. Schlage's Encode Plus Wi-Fi deadbolt carries the same pair of ratings as its mechanical B60: A156.40 Grade AAA and A156.36 Grade 1.

What changes is which product the rating belongs to. Consumer Reports points out that smart locks are just as vulnerable to forced entry as conventional ones, and that a retrofit unit added to an existing deadbolt is only as kick-, pick- and drill-resistant as that deadbolt. With a retrofit, the deadbolt grades that count are the ones on the lock already in your door.

If you are choosing between a full smart deadbolt and a retrofit, check both the smart features and the rating line. The trade-offs between the two are covered on our smart deadbolt installation page.

What a grade cannot promise

A rating describes how a lock performed in a lab. BHMA's own A156.40 announcement says field results can differ with installation, door and frame construction, maintenance and environment.

The frame is where most of that gap shows up. Consumer Reports found that many locks ship with short screws that catch only the jamb, not the house framing, and that a box strike with 3 inch screws improved kick-in resistance significantly for most locks. Even Schlage's AAA-rated B60 relies on a strike reinforcer with 3 inch screws.

So a top rating on a weak jamb is money half spent. Pair any new lock with a reinforced strike plate and long screws, and check the door type first in our overview of the different types of deadbolts.

Choosing between deadbolt grades in the store

For a home entry door, start with the A156.40 rating and look hardest at the security letter, since that category covers the attack tests. Durability matters most on a door that is locked and unlocked many times a day, and finish matters most on doors exposed to weather or salt air.

If a lock lists only one of the two deadbolt grades, that is not a red flag by itself. What matters is that the claim names a standard and shows up in the directory. When your current lock carries no rating at all, or a rating you cannot verify, swapping in a certified deadbolt usually fits the existing holes.