Rekeying Locks: Change the Key, Keep the Lock

What rekeying means

A lock is a mechanism that responds to one particular key shape. Rekeying changes which key shape the lock responds to. The lock body stays on the door, the handle and deadbolt stay where they are, and the finish and appearance do not change. What changes is the inside of the cylinder, so a new key operates it and the old key no longer does.

People rekey for many reasons. They have moved into a house and do not know who else holds a key. A key has been lost or stolen. A former roommate, contractor, tenant or employee had a key and the relationship has ended. Or they simply want all the locks on a property to work with one key instead of a bundle of different ones. In each case, the goal is the same: control over who can open the door.

Rekeying is different from replacing. A replacement removes the old lock and puts in a new one, which may include a new brand, a new finish and a new grade of security. Rekeying keeps what you have. Both are legitimate choices, and the right one depends on the condition of the lock, the level of security you need and your budget for the project, which we discuss only by phone.

This page covers rekeying in general terms. Our page on lock change and installation covers the replacement route, and the two pages work well together if you are deciding which way to go.

How a pin tumbler lock works, at a high level

Most house door locks, deadbolts and padlocks are pin tumbler locks. Inside the cylinder is a row of small spring-loaded pin stacks. Each stack is made of two or more pins of different lengths. When there is no key, the springs push the pins down so that they cross the line between the turning part of the cylinder and the fixed housing, and that crossing stops the cylinder from turning.

When the correct key goes in, its cuts push each pin stack up to a different height. At the right height for every stack, the gap between the pins lines up with the edge of the turning part. Nothing blocks rotation, and the cylinder turns. A key with any wrong cut leaves at least one stack in the way, so the lock stays shut.

Rekeying works by changing the pins. A technician removes the cylinder, takes out the existing pins and replaces them with pins of different lengths that match the cuts on a new key. When the cylinder is put back, only the new key lifts the stacks to the right height. The old key now lifts them to the wrong positions and does nothing.

That is all we describe here. The details of how locks are opened without a key are not something we publish, and rekeying itself is work for a trained technician who has the right tools, pins and knowledge of each brand. Doing it at home with a kit can leave you with a lock that works poorly or fails at the worst time.

Rekey or replace: how to choose

The choice is not always obvious. A short comparison helps.

When rekeying is the better value

Rekeying shines when the existing hardware is sound. If your deadbolts and door handles are in good condition, work smoothly and match the style of your home, you gain nothing by throwing them out. Rekeying addresses the security issue, which is who has a key, and leaves the rest intact. It is also typically a quicker job than replacement, since the technician is working on the cylinders and not removing and fitting whole assemblies.

It is also useful when you want to match several locks to one key. Many homes have a front door, a back door, a garage entry and a side door, each with its own key. If the locks are the same brand and size, a technician can often rekey them all to a single key, or to a key plan that works for your household. The convenience is real: one key on your ring instead of four.

Rekeying is sensible for rental properties too, between tenants, when you want the old key to stop working without paying for new hardware at every turnover. We cover that further below.

Remember that rekeying does not upgrade the lock. A basic builder grade lock that is rekeyed is still a basic builder grade lock. If your concern is not who holds a key but how strong the lock itself is, replacement with a higher grade lock may be the better answer. Our page on high security locks explains what the options are.

When replacing is the better choice

Some situations call for new hardware. A lock that is visibly damaged, loose in the door, hard to turn or corroded may not take a rekey well, or may continue to cause problems afterward. A lock that has been through a break-in attempt may have hidden damage to the latch, the strike or the bolt. In that case, rekeying alone does not restore its strength. Our page on lock repair after a break-in describes what to look at.

Another case is a lock of very low quality. Some inexpensive locks have loose tolerances and short bolts that are easy to defeat regardless of the key. Putting new pins in does not change that. If you are rekeying for security reasons, it is worth asking the technician to comment on whether the hardware is up to the job.

Some locks cannot be rekeyed at all. A few are manufactured as sealed units. Others have cylinders that are no longer made or cannot be matched to a standard keyway. Some commercial locks have a different system with its own rules. The technician will tell you when this is the case.

Finally, if you want a different function, such as a keypad, a smart lock or a double cylinder deadbolt, the answer is replacement. Our pages on smart lock installation and deadbolt installation cover those options.

Moving into a new home

Rekeying is one of the most common steps a new homeowner takes, and with good reason. When you buy a home, you do not know how many keys exist. The previous owner may have given copies to relatives, neighbors, cleaners, contractors, a real estate agent or a lockbox. Some of those people may no longer have a legitimate reason to enter the house. Rekeying cuts that chain in a single visit.

Do it early, ideally before or on the day you move in. Think about every exterior door and any lock that gives access to the property, including the garage entry, a side gate, a shed and a mailbox if you wish. Remember to ask about the garage door keypad code and any smart device codes, which are separate from the keys. Our guide on the moving day lock and key checklist walks through the full list.

Consider the key plan you want. Some people want all exterior locks on one key. Others prefer a separate key for the garage entry or for an outbuilding. Think about how many keys you need to cut, and for whom. A set for each adult in the household, a spare kept with someone you trust and a key for any regular helper is a common starting point.

Ask the technician to explain how the new keys work, and mark each key clearly. Keep a record of which key opens which door. When you hand over a key in the future, you will know what it covers.

Tenants, landlords and rental properties

Rekeying is common in rental housing, and the rules can be sensitive. Who may rekey, who pays and who must hold a key depend on the lease and on local and state law. We are not a source of legal advice, and the rules vary. What follows are general points to consider.

For landlords, rekeying between tenants is a standard practice. It ensures that the departing tenant and anyone they gave a key to cannot enter. Many landlords rekey all units at turnover and keep a master or a key plan for management. Our page on apartment and landlord locksmith service covers property level needs.

For tenants, the situation is more delicate. In many places a tenant cannot change or rekey the locks without the landlord's permission, and a tenant who does so without permission may breach the lease. If you are a tenant and you are concerned about safety, for instance if an ex-partner or a former roommate still has a key, talk to your landlord in writing and ask them to rekey. If you feel unsafe, contact local authorities and ask about your legal options.

A locksmith will usually ask for proof that you have the right to authorize the work. A landlord can provide ownership or a management agreement. A tenant may be asked for the landlord's written permission. This is a protective step, not a barrier, because a locksmith should not change locks for someone who has no right to do so. Be ready with the paperwork when you call.

What happens during a rekey visit

A rekey visit is usually straightforward. The technician confirms who you are and your right to authorize the work, then looks at the locks to see which are suitable for rekeying. They check the brand, the keyway and the condition. Any lock that is damaged, loose or unsuitable is noted, and they discuss the options with you.

For each lock to be rekeyed, the technician removes the cylinder from the door, takes it apart and replaces the pins with a new set to match the new key, then reassembles it and tests it. They test the lock several times with the new key and with the old key to confirm the old key no longer works. They then refit the cylinder and check that the bolt throws and retracts smoothly.

If you want several locks on one key, the technician sets up each cylinder to match the chosen key. They cut as many copies as you need. They hand you the keys and the old keys, if you wish to keep them. Keep the old keys away from the new ones, so they do not get mixed up.

The technician may point out other issues, such as a loose strike plate, a sagging door or a short bolt. They will explain what they see and whether it matters. You decide what to do. Quotes are given by phone, and where a job is complicated, an on-site visit may be needed to assess it. The service call charge is explained before anyone is dispatched.

Questions worth asking before you book

A good conversation upfront prevents surprises. Ask the following.

• Can my locks be rekeyed, or do they need replacing? Please tell me the brand if you can see it on the lock.
• How many locks do I want rekeyed, and can they all go on one key?
• How many keys will I receive and can I order more later?
• Will you test the old key to confirm it no longer works?
• What are the charges for the visit, per lock and per key, and how is the quote given?
• What proof of ownership or authority do you need from me?
• If a lock turns out to be unsuitable, what are my options and who decides?

Keeping your keys under control afterward

Rekeying works only as long as you manage the new keys. Mark them or keep a record of who has each one. Do not hand out copies casually. If you give a key to a contractor, a cleaner or a house sitter, note it down and ask for it back when the job is done. Our page on how often to rekey or change locks explains the situations that call for another round.

Avoid hiding a spare key outside. Common hiding places are well known. A better option is to leave a spare with a trusted person. Consider a keypad or a smart lock for guests and helpers, so you can issue and remove access without handing out metal keys.

Check your locks from time to time. If a key starts to stick or the lock begins to feel loose, deal with it early. A loose lock can fail and a stiff key can break. Replace worn keys, because they wear the pins inside the lock.

When you are ready to talk about your locks, call. Tell us what you have, what you want and what has happened. We will explain whether rekeying fits and what to expect.

Questions people ask

Related pages

Written by Claude (AI) (AI) for 24/7 Locksmith USA.