Keyed Alike vs Master Key Systems: Which Suits You?

Carrying a fistful of keys is one of the small daily annoyances of owning or running a property. The front door has one key, the back door another, the screen a third, the garage a fourth. Businesses have it worse, with keys for the front door, the stockroom, the office, the cabinets and the roller door. Two common solutions come up whenever people ask about this: keying locks alike, and setting up a master key system.

They sound similar but solve different problems. This guide explains how each works, the situations each suits, their limits, and how restricted keys fit in. It is written for homes, rentals, shops and offices around Lidcombe and nearby suburbs.

Keyed alike: one key opens every lock

When locks are keyed alike, every lock in the set is pinned to the same combination. One key opens all of them, and every key in the set is identical.

How it is done

For locks that share a compatible keyway, a locksmith can rekey each cylinder to the same combination. New locks can also be ordered keyed alike from the manufacturer. If existing locks come from different brands with incompatible keyways, some cylinders may need replacing to bring them onto the same system. See lock rekeying.

Where keyed alike suits best

• Homes, where everyone in the household should be able to open every external door.
• Villas and townhouses with front, courtyard, garage and internal doors.
• Security screens paired with the main door.
• Window locks, many of which share a common key anyway.

Limits of keyed alike

• All or nothing. Anyone with a key can open every lock in the set.
• A lost key exposes everything. If one key is lost, every lock should be rekeyed.
• Not suited to staff. In a business, you rarely want every staff member to open every door.

Master key systems: different keys, one master

A master key system gives different people different keys, while one or more master keys open several or all locks.

For example, in a small office:

• each staff member's key opens the front door and their own office;
• the manager's key opens every office and the stockroom;
• the owner's grand master key opens everything.

How it is done

Master keying uses cylinders pinned so that more than one key combination will operate them. It has to be planned as a whole system, with a record of which key opens which lock. It is normally done with new cylinders from a single manufacturer's range, rather than by rekeying a mix of existing locks.

Where master keying suits best

• Offices where staff need access to some areas but not others.
• Shops with stockrooms, offices or cash areas.
• Strata buildings where residents need their own unit plus common areas, and building managers need wider access.
• Rental portfolios where an agent needs a master to several properties. This is less common and needs careful thought about security.

Limits of master keying

• More planning. The system has to be designed, recorded and maintained.
• A lost master key is serious. It may mean rekeying much of the system.
• Cost. Master-keyed cylinders and planning cost more than simply keying locks alike.
• Some security trade-off. Because a cylinder accepts more than one key, a poorly designed system can be weaker than individually keyed locks. A properly designed system from a reputable range manages this.

Restricted keys: controlling copies

Both keyed-alike sets and master key systems can use either standard keys or restricted keys.

Standard keys

Standard keys can be copied at almost any key-cutting kiosk. That is convenient, but it means you never know how many copies exist.

Restricted keys

Restricted keys use a key profile that can only be cut by an authorised locksmith on the owner's instructions, often with a signature or card check. Copies cannot be made at a kiosk. For businesses and strata buildings this is what gives the system real control. See security locksmith and commercial locksmith.

Choosing between them

For a typical home

Keyed alike is usually the answer. One key for front, back, screen and garage is simpler and, as long as keys are looked after, no less secure. If you do not know how many keys exist, rekeying to a new keyed-alike combination solves both problems at once. Our rekey or replace guide helps with each lock.

For a rental

Keyed alike within each property is common. Rekeying between tenancies keeps control. Agents should keep a key register and avoid labelling keys with addresses. See our NSW landlord and tenant lock rules.

For a small shop

If only the owner and one or two trusted staff hold keys, a keyed-alike set with restricted keys may be enough. If different staff need different access, a simple master key system is better.

For an office

A master key system with restricted keys usually suits best, with a key register showing who holds each key.

For a strata building

Building-wide systems are the owners corporation's decision and usually involve a master key or restricted key arrangement for common areas. See our strata lock rules guide.

Keeping any system under control

• Keep a key register: key number, which doors, who holds it, when issued.
• Collect keys when people leave, and rekey if any cannot be returned.
• Label keys with codes, not addresses.
• Review the system every few years, or after any major change of staff or tenants.
• Store master keys securely.

What it costs, roughly

Keying a set of compatible locks alike is usually the cheapest option, because it is mostly labour. Replacing incompatible cylinders adds hardware cost. Master key systems and restricted keys cost more because of the cylinders and planning involved. You get a fixed quote for the design before anything is ordered. Our locksmith cost guide explains the general factors.

Common questions

Can my existing locks be keyed alike? Often, if they share a compatible keyway. We check on site.

Can I add a lock to my keyed-alike set later? Usually yes, if the new lock comes from a compatible range.

Is a master key system worth it for a small business? If different people need different access, yes. If not, keyed alike with restricted keys may be simpler.

What happens if a master key is lost? The affected locks should be rekeyed. That is why master keys need to be stored carefully.

Talk to us

If you are in Lidcombe, Auburn, Berala, Regents Park, Homebush or Strathfield and want fewer keys or better control over who has them, call 02 4503 6922. We are open 7 days, 7:00 AM to 12:00 AM, and we quote before we start. You can also request a quote or read about our lock replacement work.