What Those Deadbolt Ratings Mean

When choosing a deadbolt or lock, the various grading systems can be confusing. For a homeowner or business owner who wants the best security possible, it’s easier to choose when there is a clarification of terms and their associated meanings. 

Here are some grading systems a lock buyer is likely to see when trying to choose a lock, and their corresponding meanings:

What is ANSI lock grading?

ANSI stands for American National Standards Institute, and the standards were created by the Builders Hardware Manufacturers to determine the security standards for locks. What the grading represents is a barometer scale used to grade locks for both of these measures.ANSI Grading Lock industry security standards for both durability(operation) and quality (security).

The first is the strength of the lock in terms of durability during operations, which is a way to quantify how much hard use a lock can endure over time. The second measure is the quality of security the lock provides during various forms of lock picking or breaking.

Latch Length

One of the specific measures used to indicate the security of a lock is latch bolt length. Latch length makes it harder for a door to be kicked or forced in. A latch bolt length of one inch is considered to be a Grade 1 latch length. A latch bolt which is a ⅝ inch in length is a Grade 2 or 3.


The next measure of grading is based on opening and closing cycles. A Grade 1 lock has been tested to function one million times. Grade 2 and 3 locks are tested to cycle 800,000 times.


Another measure of durability is impact resistance, i.e., the number of strikes with 75 pounds of force a lock can withstand. A Grade 1 lock can withstand ten strikes of 75# force. A Grade 2 lock can withstand 5 strikes with 75# force. A Grade 3 lock can withstand 2 strikes of 75# each. 


In addition to ANSI requirements, the Underwriter’s Laboratory (UL) has determined a rating measure of lock security based on a lock’s ability to withstand picking, drilling, sawing, bumping, forcing, impressing and prying. To pass, a lock must also be able to withstand 10,000 opening and closing cycles.

ADA compliant

ADA compliance recognizes the function of a lock as to be accessible to people with disabilities. Lever size and projection from the door are two requirements measures by ADA compliance.

How to use this information to choose locks

Generally speaking, Grade 3 locks are the type used for most residential applications. Grade 2 locks are used for higher end residential applications and some commercial applications, and Grade 1 locks are used for commercial applications. All are certified by BHMA standards. However, a commercial lock should be a Grade 1 lock is the sheer volume of use. A commercial deadbolt lock has the likelihood of being required to function many more lock and unlock cycles than a typical residential lock. ADA-compliant locks are required for commercial applications.

Choosing a lock is easier if the terminology is clear, however, for the best results for a residential or commercial deadbolt situation, a locksmith can help determine which is right for a given situation.