How Rekeying Works, and How to Plan One

What a rekey actually changes

Most door locks on homes are pin tumbler locks. Inside the cylinder are small pins of different lengths, and a key works when its cuts lift every pin to exactly the right height. Rekeying means taking the cylinder apart and changing those pins for a new set that matches a different key. The lock body, the handle and the deadbolt stay on the door; what changes is which key turns them.

Old keys, every copy of them, and whoever has them, stop working the moment the pins are changed. That is the whole point.

Why rekey

• You moved in. You have no idea how many keys the previous owner, the builder, the cleaners or the realtor's lockbox handed out. See our new home lock checklist.
• Keys went missing. A lost key ring, a tenant who did not return keys, a contractor, an ex.
• Too many keys. Front, back, garage door and side gate on four different keys can almost always become one.
• The locks are good. If the hardware works and you like it, a rekey costs far less than new locks for the same security result. When new locks make more sense is covered in rekey or replace.

Before you plan: check every lock

A rekey can only put locks on one key if they share a keyway: the shape of the key blank. This is where most plans go wrong, and it takes two minutes to check.

• Count the locks. Front door knob or handle, front deadbolt, back door, door from the garage into the house, garage side door, side gate, and any sliding door with a keyed lock. People routinely forget one or two.
• Read the brand on each. It is usually printed on the face of the cylinder, around the keyhole, or on the latch plate on the edge of the door.
• Look at the keys. The shape of the head and the wording on it tell the keyway as well as the lock does.

Which locks can share a key

• Schlage and Kwikset cannot. They use different keyways: a Schlage key does not even go into a Kwikset lock, and the other way round. A house with a Schlage front door and Kwikset back doors cannot be made to work on one key by rekeying alone.
• Kwikset and Kwikset SmartKey can. SmartKey uses the same key shape as a standard Kwikset, so both can be set to the same key. See Kwikset SmartKey explained.
• Some store brands use the Kwikset or the Schlage keyway. Many budget locks sold at big box stores take one of the two. A photo of the keyhole tells us which.
• High-security cylinders are their own system. Brands with restricted keys are rekeyed or copied only through authorized dealers. See high-security locks.
• Smart locks usually still have a key cylinder. On most models it can be rekeyed like any other lock of its brand.
• Mailboxes are separate. A cluster mailbox lock is not part of the house system; see mailbox lock replacement.

When the brands are mixed

You have three choices, and we will tell you which makes sense for your doors:

• Two keys: rekey each brand to its own new key. The cheapest way to make every old key useless.
• Swap the odd ones out: replace the few locks of the other brand with matching ones, then rekey everything to one key. This is what most people end up doing, and it is often only one or two locks.
• Swap just the cylinder: on some locks only the cylinder needs to change, not the whole handle set.

Plan it in one text

Send us a photo of the face of every lock and the keys you have, with your ZIP. From that we can tell you whether everything can go on one key, which locks would need to change, and what it will take, before we drive over. The lock rekeying page covers the service itself.

Questions people ask