Rekeying vs Lock Replacement: Complete UK Locksmith Guide

When your locks no longer work reliably or you've lost keys, you have two main options: rekeying your existing locks or replacing them entirely. Both have distinct advantages, costs and situations where they work best. Understanding the difference helps you make a decision that suits your property and budget.

What Is Lock Rekeying?

Rekeying involves changing the internal pin configuration of your existing lock so it operates with a new key. A locksmith removes the lock cylinder, takes out the old pins and springs, and installs new ones that match a fresh key. The lock body itself stays in place on your door.

This process costs between £25 and £60 per lock for a standard mortice or cylinder lock. Rekeying multiple locks in your home often qualifies for discounts, bringing the average cost down to £40 per lock across 3–5 locks.

Rekeying works particularly well when:

• Your locks are in good working condition mechanically
• You've moved into a property and want to prevent previous owners or tenants using old keys
• You've lost a single key but the lock functions normally otherwise
• Your current locks match your door aesthetic and security requirements
• You need a quick solution without replacing door hardware

What Is Lock Replacement?

Lock replacement means removing the entire lock mechanism and installing a brand new one. A locksmith uninstalls the old lock cylinder, removes fixings, and fits a completely new lock with fresh keys. You receive new key blanks and the original factory key cuts.

Replacement costs vary based on lock type. A standard pin tumbler cylinder replacement runs £50 to £120, whilst upgrading to a high-security lock costs £120 to £300 per lock. Installation labour typically adds £30 to £50 per lock.

Lock replacement becomes necessary when:

• Your lock is damaged, broken or won't turn smoothly even after cleaning
• You want to upgrade to a higher security standard (BS 3621 or 5-star rating)
• The lock is outdated and replacement parts are no longer available
• You've had a break-in and need to improve security beyond the original specification
• The lock cylinder is seized, corroded or showing signs of wear that affects reliability

Cost Comparison

Rekeying is the budget option in almost every scenario. A single rekey costs £25 to £60 versus £80 to £170 for basic replacement including labour. For a terraced house with five external locks, rekeying runs roughly £175 to £300, whilst replacement would cost £400 to £850.

Replacement costs become more justified when security upgrades matter. A BS 3621 approved lock costs more initially but typically offers 10 years of manufacturer support and superior anti-pick, anti-snap properties. After 5–7 years, replacing a low-security lock twice might match the cost of upgrading once.

Think about long-term value: a £40 rekey followed by another £40 rekey three years later costs £80 total, but a £150 high-security replacement needs only one installation for potentially 15+ years of reliable service.

Security Considerations

Rekeying provides adequate security for standard residential situations. Your old keys become useless immediately and only the new key operates the lock. This solves issues from lost keys or previous occupants.

However, rekeying doesn't improve the lock's inherent security rating. If your original lock is a basic five-pin cylinder, rekeying keeps it at that level. Burglars with lock-picking tools still encounter the same difficulty.

Replacement allows you to choose locks with enhanced security features:

• Anti-snap cylinders that prevent forced removal of the cylinder
• Additional pins and complex keyways making picking harder
• Reinforced internal components resisting drilling and bumping
• Certification from approved bodies like Loss Prevention Certification Board

If your property has experienced break-ins or sits in a high-crime area, replacement with certified high-security locks provides substantially better protection than rekeying existing basic locks.

When to Choose Rekeying

Rekeying is the practical choice when your existing locks work perfectly but you need new keys. This applies to new homeowners, tenants after a previous occupant, or anyone who's lost their key set.

Choose rekeying if your locks are:

• Mechanically sound with no sticking or resistance
• Functioning locks from reputable manufacturers
• Aesthetically matched to your doors and decor
• At least 5–10 years old with no obvious wear
• Insured at their current security rating

The main advantage is simplicity and cost. Installation takes 15–30 minutes per lock, you keep identical external appearance, and minimal disruption occurs to your door frame or paintwork.

When to Choose Replacement

Choose lock replacement when mechanical problems exist, security needs upgrading, or you want newer technology. If your lock sticks when opening, requires key jiggling, or shows visible corrosion, replacement eliminates these frustrations entirely.

Replacement also suits property improvements. Installing matching high-security locks across all external doors provides peace of mind that all access points meet modern standards. Many insurers recommend or even require BS 3621 locks for buildings insurance, making replacement a smart investment.

New construction or renovations often justify replacement costs through coordinated aesthetics. Choosing locks that match door handles, hinges and other hardware creates a cohesive appearance impossible when rekeying older mismatched locks.

Making Your Decision

Start by assessing your locks' mechanical condition. Twist each key firmly. If the lock turns smoothly without resistance, rekeying likely solves your issue. If you feel grinding, sticking or resistance, replacement prevents future problems.

Next evaluate your security needs. Check your home insurance requirements and local crime statistics. If your neighbourhood requires BS 3621 locks, replacement pays for itself through lower premiums and genuine security improvement.

Finally, consider your timeline. Need keys today? Rekeying takes hours. Planning renovations or moving across several months? Replacement allows you to research certified locks and coordinate installation with other work.

Most UK homeowners benefit from a mixed approach: rekeying locks that function perfectly, replacing those showing mechanical wear or failing to meet insurance requirements. This balances budget constraints with practical security needs.

Compare quotes from 3 providers for both options, as labour rates vary significantly by region and lock type. Locksmiths in London and the South East typically charge 15–20% more than provincial rates.