Lock Buyer’s Guide
The main lock types side by side, what each one suits, and the choices that decide the cost of a new lock, without prices.
Choosing a lock starts with the door. A front door with glass beside it, a rental that changes tenants, a back door used all day and a storefront each call for something different, and the holes already cut in the door decide how easily a new lock fits.
Most outside doors carry two locks: a deadbolt that does the securing, and a knob or lever whose spring latch holds the door shut day to day. The real decisions are about the deadbolt: how it opens, whether it needs power, and who controls the keys.
Weigh Two or Three Locks Side by Side
Most choices narrow to two or three types. What matters is how each one opens, what it needs to keep working, and what to weigh before it goes on.
Pick the Locks to Compare
Tick two or three.
Tick two or three lock types, then press Compare These Locks.
How the Main Lock Types Differ
| Lock type | Best for | Key or code | Power needed | Things to consider |
|---|---|---|---|---|
| Single-cylinder deadbolt | Most front, back and side doors | Key outside, thumb turn inside | None | A thumb turn near glass can be reached through a broken pane |
| Double-cylinder deadbolt | Doors with glass in or beside them | Key on both sides | None; fully mechanical | Getting out takes the key; check local codes first |
| Keypad deadbolt | Rentals, busy family doors | Code, with a key as backup | Batteries in the inside unit | Codes need changing when people move out |
| Smart lock | Letting people in from somewhere else | App, code or key, by model | Batteries, plus Wi-Fi or a hub | Relies on the app and the signal at the door |
| High-security cylinder | Storefronts, offices, tight key control | Restricted key most key counters cannot copy | Not needed | New keys go through whoever holds the key record |
| Lever or knob lockset | Daily latching, and inside doors | Key outside, button or turn inside | No power at all | Its spring latch is not a deadbolt |
Levers are easier than knobs for a weak grip or full hands, and on an outside door either one pairs with a deadbolt. Whatever the type, a bolt is only as strong as the strike and the frame it locks into.
Six Things Behind the Cost of a Lock
The cost of a lock job follows the lock, the door and the keys, and several of these factors are choices you can settle before any work starts.
| Factor | How it affects cost | What you can decide |
|---|---|---|
| Lock type | Keypad and smart locks add electronics, so they cost more than mechanical ones | Whether a code or an app earns its place |
| Grade | A heavy-duty Grade 1 lock costs more than a lighter Grade 3 lock | The grade that matches how hard the door is used |
| Door prep | A door already bored for a standard lock is quickest; new holes or a mortise pocket add work | A lock that fits the holes already in the door |
| Keying | Matching several cylinders to one key, or to a master key, adds work per lock | Which doors should share a key |
| Key control | Restricted keys cost more to cut | How many keys you need, and who may order more |
| Door and frame | A worn strike, split jamb or sagging door has to be put right first | Whether to sort out the door at the same time |
What do lock grades mean?
Many locks are graded under ANSI/BHMA standards for strength and for how many cycles they last. Grade 1 is the heaviest duty, for busy commercial doors; Grade 2 suits most homes; Grade 3 is the lightest.
Can a new lock work with the keys I already have?
Often it can. If the new lock takes the same key blank as your old keys, its cylinder can usually be rekeyed to match. Makers use different keyways, so check before you buy.
Do keypad and smart locks cost more to keep?
Mostly in batteries and attention: batteries need replacing, more often on a door in full sun, and codes need changing as people come and go. A mechanical deadbolt asks only for a dry lubricant now and then.
Working Out Which Lock to Buy
- Measure the door: its thickness (most are 1 3/8 to 1 3/4 inch), the bore hole (usually 2 1/8 inch) and the backset from the edge to the center of the hole (2 3/8 or 2 3/4 inch).
- Decide who needs to get in and how: keys, a code for a cleaner, or an app to let someone in from work.
- Decide on keys: one key for every outside door, a master key across several locks, or restricted keys only you can order.
- Pick the grade for the door’s use; a storefront or a rental’s main entry sees far more use than a bedroom door.
- Check the frame: the bolt should meet the strike squarely, and the strike should be held by long screws in solid wood.
- Narrow it to two or three types, and weigh how each is powered and what happens when its battery runs out.
A door that has never had a deadbolt, or whose old holes do not match the lock you want, needs boring or patching first, which is best done with a jig. For a door like that, book a visit and mention the lock you have in mind.
Questions to Settle Before Buying a Lock
- Does the door need a deadbolt, a latch, or both?
- Is there glass within arm’s reach of the inside thumb turn?
- Should every outside door open with the same key?
- Who needs a code or app access, and who changes the codes when people move out?
- If you rent, does the lease allow a lock change, and does the landlord need a key?
- Will a dark finish sit in full afternoon sun, where Phoenix heat makes it hot to the touch?
- What happens on the day the batteries run out?
Once the answers point to a lock, the next step is fitting it to the door: new deadbolts, keypad locks and smart locks on the door you already have.