How to Choose a Deadbolt — ANSI Grade, UL 437, Function & Key Control
Choosing the right deadbolt comes down to four factors: ANSI grade, UL listing, function, and key control. This guide breaks down each one so you can choose the best deadbolt for your home or commercial application. Questions? Contact us or call 954-776-5340.
Factor 1
ANSI Grade — the industry standard for deadbolt quality
The American National Standards Institute (ANSI) grading system — developed by the Builders Hardware Manufacturers Association (BHMA) — rates deadbolts from Grade 1 (highest) to Grade 3 (lowest), factoring in longevity, toughness, and bolt length.
Grade 1 — Commercial / Maximum Security
Tested to withstand 1 million open/close cycles. 1" bolt. Withstands 10 strikes of 75 lbs force (150 ft-lbs). Used in commercial applications or where the highest level of security is required.
Grade 2 — Residential
Tested to withstand 800,000 open/close cycles. 5/8" bolt. Withstands 5 strikes of 75 lbs force (120 ft-lbs). A solid mid-grade lock at a mid-range price — the most common choice for residential front doors.
Grade 3 — Secondary Security
Tested to withstand 800,000 open/close cycles. 5/8" bolt. Withstands 2 strikes of 75 lbs force (90 ft-lbs). Best used as a secondary security measure rather than a primary lock.
Factor 2
UL 437 — the toughest independent security rating
Defined by Underwriters Laboratories, UL 437 is one of the hardest security ratings to achieve. It tests deadbolts against impressioning, forcing, drilling, sawing, prying, picking, and lock bumping.
Lock bumping uses a special bump key to open a pin tumbler lock in seconds — a skilled attacker can do it nearly instantly. A UL 437-rated deadbolt is engineered to resist this technique.
UL 437 also tests for field-changeable keys, tight-fitting bolts, and the ability to withstand 10,000 open/close cycles.
Factor 3
Deadbolt function — which type do you need?
Single Cylinder
Double Cylinder
One-Sided With Trim
One-Sided No Trim
Thrown or retracted by key from outside and by thumb turn on inside. The most common deadbolt for residential front doors.
Keyed on both sides — prevents an intruder from breaking a nearby window and reaching in to unlock. Check local building codes as this type may not be permitted in some areas.
One-Sided Deadbolt With Outside Trim
Thrown or retracted from the interior only. Exterior trim plate covers the exposed door prep on the outside. Ideal for back doors where outside access isn't needed.
One-Sided Deadbolt Without Outside Trim
Thrown or retracted from the interior only with no plate or trim on the exterior. Used when the bore hole does not go all the way through the door.
Factor 4
Key control — restrict who can copy your keys
Even the strongest deadbolt can be compromised if unauthorized copies of your key exist. True key control means only you can authorize duplicates — not just anyone who walks into a hardware store.
Mul-T-Lock deadbolts provide superior key control. Each lock comes with a unique key card — duplicate keys can only be made when the card is presented, and only by authorized Mul-T-Lock dealers.
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Need a recommendation?
We carry deadbolts for both residential and commercial applications. Contact us or call 954-776-5340 and we'll help you find the right lock. Browse our full deadbolt collection or return to the Help Center.