Deadbolt grades explained: Grade 1, 2, 3 and AAA

October 29, 2026

By the Pink Locksmiths editorial team. Updated November 4, 2026.

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Grade 1 is the highest residential deadbolt grade under the ANSI/BHMA standard, and Grade 3 is the lowest. Pick up a deadbolt box at the hardware store and you will usually find a grade somewhere on it. Sometimes it is “Grade 1”, sometimes three letters like “AAA”, sometimes nothing at all. These marks come from real standards, and once you know which one you are looking at, they tell you more than the price does.

Who writes the grades

Lock grades come from ANSI/BHMA standards. BHMA is the Builders Hardware Manufacturers Association; ANSI approves the standards it writes. A manufacturer sends a lock to a test lab, the lab runs it through the procedures in the standard, and the lock earns a rating.

Two standards matter for a front door at home.

The older one: Grade 1, 2 or 3

For a long time deadbolts were simply graded 1, 2 or 3 under the auxiliary lock standard, today A156.36 (earlier editions sat under A156.5). Grade 1 is the highest and is what you would expect on a commercial building. Grade 2 is common on good residential hardware. Grade 3 is the minimum.

The weakness of a single number is that it rolls everything into one verdict. A lock could be very durable and only average at resisting attack, and the number would not tell you which.

The newer one: three letters

A156.40 is the residential standard, and it scores a lock separately in three categories:

• Security: how the lock holds up to forced entry tests.
• Durability: how many operating cycles it survives.
• Finish: how the surface resists corrosion and wear, tested to the finish standard A156.18.

Each category gets A, B or C, with A the highest. A lock rated “AAA” got the top mark in all three. A lock rated “BAB” is better on durability than on security or finish. That is useful information if you are buying for a coastal house where salt eats cheap finishes, or for a side door that gets used fifty times a day.

Ratings on the shelf today usually cite the 2015 edition. BHMA has since published a 2025 edition, so expect to see both years on packaging for a while.

What to actually do in the aisle

Look for a grade printed on the box or the product page. If there is none, do not assume one. Manufacturers who have paid for testing tend to say so.

For an exterior door at home, a Grade 2 lock or a residential rating with an A in security is a sensible floor. Grade 1 or AAA costs more and is worth it on the door you actually use as your main entrance.

Check the door thickness before you buy. Most deadbolts list the range they fit, and a lock outside that range will not seat properly no matter how good its rating is.

An example that carries both ratings

The source for these figures is Schlage’s own product page, which lists the standards by number. That is what you want to see from any brand: the standard and the grade, not just the word “secure”.

A grade is only as good as the door around it

The lab tests the lock on a test fixture. Your house has a wooden jamb, a strike plate held by short screws, and possibly a gap between the door and the frame. A Grade 1 bolt sitting in a weak jamb is still a weak door. The strike plate and its screws are the cheapest part of the whole setup to upgrade, and see why door frames fail before deadbolts do.

If you would rather have a professional fit the lock and check the frame at the same time, a local locksmith can usually do both in one visit. Ask for the price of the lock, the labor and the trip separately so you can compare quotes.