What a lock's grade actually measures

The Builders Hardware Manufacturers Association, BHMA, is the body accredited by ANSI to write performance standards for door hardware in the United States. Its standards are why a lock can claim Grade 1 or carry a certified label. They are real, third-party-tested standards, and they are worth paying attention to. They also measure different things, on different scales, and the shorthand people use for them blurs that.

Scale one: Grade 1, 2, 3 (lower number is better)

BHMA's own page on grade levels says many of its standards define "grade 1, 2, or 3 -- with grade 1 being the highest," set by "progressive levels of performance benchmarks in each applicable ANSI/BHMA standard." Note the last words. Each product category has its own standard, and a grade means something only inside that standard.

Allegion, the parent of Schlage, published a short explainer on this in 2013 that is unusually candid for a manufacturer. It makes three points that matter here. First, Grade 1 "is designed for heavy-duty applications and mostly includes commercial hardware," in the words of an Allegion specification manager. Second, two product categories can both be Grade 1 without being judged the same way: "A mortise lock and a cylindrical lock are not judged by the same standards, nor should they be." Third, and most important:

The most significant difference between the ANSI/BHMA grades is the cycle test.

A cycle test asks how many times the lock can be operated and still work. Allegion's 2013 table gives bored (cylindrical) locks 1,000,000 cycles at Grade 1, 400,000 at Grade 2 and 200,000 at Grade 3. For mortise locks it lists 1,000,000 at Grade 1 and 800,000 at both Grade 2 and Grade 3. The grades do include strength and security tests too (the explainer lists items such as bolt strength, deadbolt torque and impact). But by the industry's own account, the line that separates a Grade 1 from a Grade 2 most is longevity. That is exactly what you want on a hotel corridor or a school. It is not the same thing as harder to defeat.

Scale two: the residential label (A is best)

In 2014, BHMA decided residential hardware was different enough from commercial hardware to need its own standards. There are two: ANSI/BHMA A156.39 for residential locksets and latches, and A156.40 for residential deadbolts. Certified products carry what BHMA calls the Secure Home label, which rates three things separately:

• Security, which BHMA defines as "how well a lock or deadbolt can withstand impact, whether from a possible intruder or extreme weather conditions."
• Durability, meaning function after repeated, long-term use and with weight hanging on the door.
• Finish, meaning resistance to sun, humidity, salt and the oils in your hands.

Each gets a letter: C for good, B for better, A for best. So a deadbolt can be A for finish and C for security, and still carry the label. BHMA's own examples show exactly those kinds of mixed combinations. If you only remember that it's certified, you've thrown away the one letter you cared about.

BHMA's FAQ gives the scale of the tests as written in the 2015 editions. Residential locksets go through at least 400,000 open-and-close cycles with a 5-pound load and a series of 11 security tests. Residential deadbolts get the same cycle count and seventeen security tests, one of which involves "having 1,350 pounds of force loaded against the deadbolt."

Scale three: high-security cylinders (C is best)

Neither scale above is mainly about the attacks people picture when they think about a quiet, skilled entry: picking, decoding, drilling the cylinder, or getting hold of a copy of the key. Those are the subject of a different standard, ANSI/BHMA A156.30 for high-security cylinders, which covers mechanical and electromechanical cylinders. BHMA's summary of the 2025 edition describes three groups of tests:

• Key control: limiting who can get key blanks or electronic credentials that would work the lock, including cylinder marking restrictions and, for electronic cylinders, audit trails and time zoning.
• Destructive tests: plug pull, impact pull, torque, and a drill resistance test lasting "5 minutes total for level “B”, and ten minutes for the highest level “C”."
• Surreptitious tests: minimum key changes, pick resistance "through either decoding or picking," and for electrified cylinders, "electrical pick resistance through over voltage," magnets or conductive liquids, plus a tolerance test of up to 100,000 cycles for the top level.

And here is the trap. In A156.30, BHMA says the three levels "describe increasingly higher protection, with level “C” being the highest." On the residential label two sections up, C is the lowest. Same association, same letters, opposite direction. If someone tells you a cylinder is rated C, the very first question is which standard they mean.

What none of these ratings certify

A lock standard certifies a lock. It doesn't certify the door it is mounted in, the frame, the strike plate and how far its screws reach into the framing, the glass sidelight two feet from the thumb turn, or the app that can open an electronic lock from anywhere. Even Allegion's explainer ends by pointing buyers to a hardware consultant for "door design, strength, reinforcement, casing and locking devices," which is a polite way of saying the lock is one part of a system.

This is the part I'd stress for high-value homes. An expensive entry often has a heavy custom door and a carefully chosen lockset, and then a standard strike, a big glass panel, or a smart lock whose app account is the softest point on the opening. The rating on the lock is honest about the lock. It is silent about everything around it.

Why this beat cares

I help design the AI security systems for a veteran-owned (SDVOSB) home-security company run by fellow veterans. I do not own that company and earn nothing from this link. Full policy here.

Counter-IED work teaches you to ask of any protective measure what it was actually tested against, and by whom. Lock ratings pass that test better than most consumer security claims, because the testing is third-party and the standards are published. The problem is only that three different scales get collapsed into one word.

What to do with this

• Check the directory, not the box. BHMA certification is voluntary and requires independent lab testing. Look the exact model up in the BHMA Certified Products Directory, and note which standard it is listed under.
• On residential hardware, read all three letters. For an exterior door, the security letter is the one that matters most. An A for finish tells you nothing about forced entry.
• If picking, drilling or key copies are your concern, ask for A156.30. Ask for the level on each category, and remember that in this standard C is the top.
• Treat Grade 1 as mostly a durability claim. It is a good sign for a door that gets heavy use. It isn't, on its own, evidence of attack resistance.
• Spend on the opening, not only the lock. Frame, strike reinforcement, glass near the lock, and a door contact on the alarm. A lock that is forced or bypassed should still trigger detection.

What I could not confirm

I read BHMA's summaries, not the standards. The full A156.30, A156.39 and A156.40 documents are sold separately and I did not open them. Everything above comes from BHMA's own public summaries and FAQ, which BHMA notes are "not a substitute for the full standard."

The cycle numbers are from a 2013 document. Allegion's table reflects the standards of that time. Later editions may have changed the counts, and I have not checked them against current editions.

BHMA's A156.30 summary has a rough patch. Its worked example of a cylinder designation is hard to reconcile with the text around it, so I have not used it. The level definitions I quote are stated directly.

Nothing here evaluates or recommends any specific lock, cylinder or manufacturer. Allegion appears because it published the explainer quoted, not as an endorsement of its products.

The signal

Door-lock ratings are real and worth using, but they are three scales, not one. Commercial grades run 1 to 3 and differ most in how long the lock lasts. The residential label rates security, durability and finish separately from C to A. And the standard that actually addresses picking, drilling and key control, A156.30, ranks its levels with C at the top. Ask which standard, read every letter, and remember that no lock rating says anything about the door around it.