Can a Single Key Open Every Lock in Your NYC Apartment?

Often yes for the locks on your own doors, and usually no for the two you would most like to include. Keyed-alike is a real service, it is cheaper than people assume, and it is limited by one physical constraint that decides every case before anyone quotes you a price.

That is the short version. The constraint is the keyway, and understanding it tells you in advance which of your locks can join the set.

What keyed-alike actually is

It is not a product you buy. It is a rekey.

Every pin-tumbler cylinder has a stack of small pins inside, cut to heights that match one specific key. Rekeying means swapping those pins for a different combination so the cylinder answers to a different key. Keyed-alike means doing that to several cylinders at once, to the same combination, so one key opens all of them.

Nothing is added to the door and nothing is replaced. The hardware you already own keeps working exactly as before, answering to one key instead of four. That is why it costs what a rekey costs rather than what new locks cost.

The one condition that decides everything

Cylinders can only be keyed alike if they take the same keyway. The keyway is the shape of the slot the key slides into, and it varies by manufacturer and product line: Schlage, Kwikset, Yale, Arrow, Sargent, and the Segal-style vertical deadbolts common across pre-war Brooklyn and Manhattan all have their own.

A key blank cut for one keyway will not enter another. This is a physical fact about the metal, not a policy, and no amount of pinning works around it. If your deadbolt is a Schlage and your knob is a Kwikset, they cannot share a key while both stay on the door.

That leaves two options when the keyways differ. Either change one cylinder so both match, which turns part of the job into a hardware replacement, or accept two keys. Which is better depends on the hardware you have, and it is the first thing a locksmith should tell you when they look at the door.

The practical version: matching keyways get keyed alike as a rekey. Mismatched keyways need a cylinder swap first. Ask which situation you are in before agreeing to anything.

What can usually be keyed alike

• Your apartment knob and deadbolt. The most common request, and it usually works. Two cylinders, one key.
• A brownstone or townhouse set. Front door, vestibule, basement, and roof-deck door. This is where keyed-alike earns its keep, because four keys becomes one.
• Rim cylinders and Segal-style vertical deadbolts, common in pre-war stock, can be brought into a set where the keyways allow.
• A gate or garage side door, if the cylinder is compatible.
• High-security cylinders like Medeco, Mul-T-Lock, and Schlage Primus can be keyed alike, but only within the same system and through the authorized dealer, since the blanks are restricted. If you want one restricted key for several doors, say so at the time the system is set up rather than a year later.

What usually cannot, and why

Your mailbox. Mailbox locks are small cam locks, a different hardware family from a door cylinder, and they generally cannot join a door key set. There is a second problem too, which is that changing a mailbox lock is not always your decision: it depends on whether USPS or your landlord controls the box. We set out who can authorise what in mailbox lock replacement in NYC.

The building entrance or vestibule door in a rental. That lock is not yours. It usually sits on a building master key system so the super’s key opens it, and rekeying it to your key would lock the building out of its own door. In a rental, the building entrance is off the table.

Fobs, keypads, and app-based locks. These are not mechanical keys and there is nothing to pin. A smart lock with a physical override cylinder can sometimes have that cylinder brought into a set, which is worth asking about, but the electronic credential is separate.

Anything on a master key system you do not control. If your apartment cylinder is keyed so the building master also opens it, that has to be preserved, and any keyed-alike work has to be designed around it rather than ignoring it.

The trade-off nobody mentions

One key for everything is convenient every day and expensive on the day you lose it.

With four different keys, losing one compromises one lock. With a keyed-alike set, losing the single key compromises every door it opened, and the fix is rekeying the whole set rather than one cylinder. That is not a reason to avoid it. It is a reason to be deliberate about what goes in the set.

The sensible line for most people is that doors protecting the same space belong together, and doors protecting different spaces do not. Your apartment knob and deadbolt guard one opening and obviously belong on one key. A storage cage in the basement, or an office, guards something separate, and there is a real argument for keeping it apart.

Two practical habits go with a keyed-alike set. Do not put anything identifying on the keyring, because now one found key with an address attached opens everything. And get spares cut at the time of the work, since key duplication is $30 to $85 per key and cheaper to do while the locksmith is already there.

If you rent or live in a co-op

Two things to settle before booking.

Check your lease for a key-on-file requirement. Many NYC leases require the landlord to hold a working key. A keyed-alike rekey is fine, but the landlord’s copy has to be updated with it, and that is a conversation rather than an afterthought.

Check whether your cylinder is on the building master. In buildings where the super’s master opens apartment doors for emergencies, a rekey has to preserve that. It is straightforward to do, and it has to be specified rather than discovered afterwards.

Rekeying itself makes no change to the door, the frame, or the strike, and is fully reversible, which is why it usually falls outside the alteration approval a hardware change would need in a co-op. Tell the managing agent anyway.

What it costs

Job	NYC cost
Rekey, per cylinder	from $75
Typical apartment, knob and deadbolt keyed alike	$150 – $185
Key duplication, per key	$30 – $85
Lock installation or replacement, per opening	$125 – $450
High-security cylinder, restricted keyway	quoted on site

Keyed-alike is priced per cylinder, because that is the work: each one is taken apart and re-pinned. A brownstone with four doors is quoted as a package rather than four separate visits. If a keyway mismatch means one cylinder has to be replaced to join the set, that line moves into the installation row, which is why you want the door looked at before the number is agreed.

We do this across all five boroughs through our lock change and rekeying service, and we will tell you honestly on arrival which of your locks can join the set and which cannot.

Frequently Asked Questions

Can one key open every lock in my NYC apartment?

Usually your own doors can share a key, provided the cylinders take the same keyway. Your knob and deadbolt are the common case and it normally works. The building entrance in a rental and your mailbox generally cannot join the set.

Is keyed-alike the same as rekeying?

Yes, it is rekeying several cylinders to one combination rather than to separate ones. Nothing is added to the door and no hardware is replaced, which is why it costs from $75 per cylinder rather than the price of new locks.

Why can’t my knob and deadbolt share a key?

Almost always because they are different brands with different keyways, so a single blank physically cannot enter both. The options are replacing one cylinder so the keyways match, or keeping two keys.

Can I include my mailbox key?

Generally no. Mailbox locks are small cam locks in a different hardware family, and there is a separate question of whether USPS or your landlord controls the box, which decides who may change it at all.

Is it less secure to have one key for everything?

It concentrates the risk. Losing one key now compromises every door it opened, and the remedy is rekeying the whole set. Keep doors that protect the same space on one key, keep genuinely separate spaces separate, and put nothing identifying on the keyring.

Can high-security locks be keyed alike?

Yes, within the same system, through the authorized dealer, because the blanks are restricted. It is much easier to specify when the high-security cylinders are first fitted than to retrofit later.