TL;DR

• Rekeying locks changes the key, not the hardware – A locksmith adjusts the internal pins so your old key no longer works.
• Lock replacement means installing brand new hardware – This is best for damaged, outdated, or upgraded security systems.
• Rekeying is generally cheaper and faster – It is a cost-effective option after moving house, losing keys, or managing multiple locks.
• Replacing locks offers stronger security upgrades – New deadbolts, smart locks, and modern systems provide higher protection.
• A professional locksmith can help you choose the right option – Expert advice ensures your doors and property stay secure.

If you have ever searched for answers after losing a key or moving into a new property, you have probably asked yourself: What is the difference between rekeying locks and replacing a lock?

It is a common question. Many homeowners and business managers are unsure whether they should rekey locks, change locks entirely, or install brand new locks for better security. The decision matters – not just for cost, but for long-term home security, convenience, and peace of mind.

In this guide, we will explain what is rekeying a lock, how lock rekeying compares to full replacement, the pros and cons of each option, and how much does it cost to rekey or replace. By the end, you will know exactly when to choose rekeying and when replacing a lock is the smarter investment.

What Is Lock Rekeying?

Definition

Rekeying locks is the process of altering the internal components of a lock so that an old key no longer works. Instead of removing the existing locks from your doors, a locksmith changes the internal pins and tumblers inside the lock cylinder.

The external hardware stays in place. The lock itself remains installed. What changes is the key that operates it.

In simple terms, lock rekeying involves altering the internal locking system so that a new key works and the old key is rendered useless.

How Rekeying Locks Works

When a professional locksmith performs a rekey lock service, they remove the lock cylinder and replace or adjust the pins inside. These pins are what allow a key to turn the locking system.

Once adjusted, the lock will only operate with a new key. Any lost, stolen, or previously issued key will no longer grant access.

Rekeying does not involve installing new hardware. It focuses on modifying the internal components while keeping the existing locks intact.

Common Situations for Rekeying Existing Locks

There are many practical reasons to rekey locks rather than replace them entirely:

• You have recently moved into a new home and do not know who may still have copies of the old key
• Your keys have been lost or stolen
• Tenants or staff have moved out
• You want to consolidate multiple locks so they operate with the same key
• You are managing a property and need better key control

In many cases, rekeying locks is generally cheaper and far more convenient than changing locks altogether.

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What Is Lock Replacement?

Definition

Lock replacement involves removing the entire lock mechanism from the door and installing a new lockset or deadbolt.

Unlike rekeying, which keeps the original hardware, replacing a lock means discarding the old lock and fitting brand new locks.

How Lock Replacement Works

When you replace a lock, the locksmith removes the entire unit from the door, including the cylinder, internal components, and sometimes the strike plate. A new set of hardware is then installed.

This process often includes:

• Installing new hardware
• Fitting a new key set
• Upgrading to a stronger locking system
• Installing modern features such as smart locks

Replacement can also involve upgrading to a higher security system for both residential and commercial doors.

When Replacement Is Best

There are situations where replacing locks is the better solution:

• The old lock is broken or worn
• The locking system is outdated
• You want to upgrade to premium or smart lock technology
• The lock hardware is damaged
• You require improved security features

If your existing locks are physically compromised, rekeying will not solve the underlying problem.

Side-by-Side Comparison

Here is a clear breakdown of the difference between rekeying locks and replacing locks:

What It Does

• Rekeying locks: Changes the key without changing the hardware
• Replacing locks: Removes the old lock and installs new hardware

Cost

• Rekeying: Generally cheaper
• Replacing: Higher cost due to new hardware

Time Required

• Rekeying: Quick and efficient
• Replacing: Longer work due to full installation

Security Improvement

• Rekeying: Moderate – same hardware, new key
• Replacing: High – new hardware and upgraded security

Best For

• Rekeying: Lost keys, recently moved, key consolidation
• Replacing: Broken locks, security upgrades, worn hardware

DIY Possible?

• Rekeying: No – specialist knowledge is required 
• Replacing: Possible with skill, but professional installation recommended

Pros & Cons of Rekeying vs Replacing

Rekeying Locks – Pros

• Lower cost compared to full lock change
• Quick, often same-day service
• Keeps existing hardware intact
• Allows multiple locks to work with one key
• Cost-effective for managing access across a property

Rekeying Locks – Cons

• Does not improve hardware security
• Only suitable if the current lock is in good condition
• Cannot fix broken or worn mechanisms

Replacing Locks – Pros

• Opportunity to upgrade to stronger locks
• Enhanced security features
• Fresh hardware and brand new locks
• Ideal for upgrading to smart locks or new deadbolt systems

Replacing Locks – Cons

• Higher cost
• Potentially longer installation process
• More labour-intensive than rekeying

While replacement allows you to upgrade to stronger, modern locks, it is important to note that some upgrades are limited by existing door cutouts. In certain cases, doors may need to be patched, painted, or modified to suit new hardware, which can add time and cost.

How Much Does Rekeying Cost?

Rekeying Locks Cost

When clients ask, “How much does it cost to rekey locks?” the answer depends on several factors:

• Number of locks
• Whether you are rekeying multiple locks to one key
• Call-out fees
• After-hours emergency service
• Accessibility of doors

Rekeying locks is generally cheaper than replacing hardware because it involves altering internal pins rather than installing new hardware. For many homeowners and businesses, rekeying offers a cost-effective way to restore security without replacing all my locks.

In most cases, both rekeying and lock replacement services start from around $150, depending on location, access, and job complexity. Because there are many variables, the most reliable way to understand costs is to request a personalised quote from a reputable locksmith.

Cost for Lock Replacement

Replacing locks typically involves:

• Purchasing a new lock or deadbolt
• Labour for installation
• Potential upgrades to security systems
• Hardware enhancements

If you are upgrading to smart locks or high-security locking systems, costs increase accordingly.

For tailored solutions, it is always best to request a free quote from a professional locksmith.

When to Choose Rekeying vs Replacement

Choose Rekeying If

• You have recently moved into a new home
• Keys have been lost or stolen
• You want one key for multiple doors
• Existing locks are in good condition
• You need a fast, cost-effective solution

In these situations, rekeying locks provides convenience and restores security without the expense of brand new locks.

Choose Replacement If

• Locks are damaged or broken
• The locking system is outdated
• You want to upgrade security
• You prefer modern smart locks
• The hardware is worn or unreliable

If the structural integrity of the lock is compromised, replacing it is the safer long-term choice.

It is also worth noting that better security does not always require new hardware. In commercial environments, upgrading to a restricted key system through professional lock rekeying can significantly improve access control without replacing existing locks.

Why Hire a Professional Locksmith

While DIY kits exist, a professional lock rekeying service ensures the job is done correctly.

Rekeying involves precision tools and experience. A professional locksmith can:

• Avoid damage to doors and hardware
• Ensure the locking system functions smoothly
• Provide security advice
• Re-key multiple locks efficiently
• Install and upgrade locks properly

For commercial properties, master locksmiths can also assess master key systems, access control needs, and broader security system integration. Attempting to rekey a lock without proper tools can lead to damaged components or compromised security.

It is also important to be cautious of extremely low advertised prices. Some unqualified operators promote call-out fees as low as $40–$50, then deliberately damage locks on site and charge thousands for unnecessary replacements. If a price seems too good to be true, it usually is. Always check company details, reviews, and licensing. In Queensland, professional locksmiths must hold a valid security licence.

Conclusion

The difference between rekeying locks and replacing a lock comes down to purpose.

Rekeying locks is cost-effective, convenient, and ideal when you need to change keys without replacing hardware. It is generally cheaper and quicker, especially after moving into a new home or losing keys.

Replacing locks, on the other hand, is best when security upgrades, damaged hardware, or modern features are required.

If you are unsure which option suits your property, business, or doors, our experienced locksmith team can assess your situation and recommend the right solution.

For expert advice, tailored solutions, and a free quote, contact John Barnes Group today. Our professional locksmith services across QLD and NSW are equipped to help you secure your property with confidence.