Changing the locks is one of those jobs almost every homeowner faces sooner or later — moving in, losing a key, an ended relationship, or a lock that has simply worn out. The good news is that it is rarely as expensive as people fear, and knowing how the cost breaks down puts you in a strong position before you call anyone. This guide gives you honest 2026 numbers for changing house locks in the UK, room by room and lock by lock, plus the one question that decides whether you even need a new lock at all.
For a single door, changing one lock typically runs £85 to £190 fitted, depending on the type of lock and how good a one you choose. To change every external lock in an average three-bedroom house, most people pay somewhere between £200 and £350 all in. The spread is wide because no two homes have the same doors — a flat with one composite front door is a very different job from a house with a uPVC front, a timber back door and patio doors.
The single biggest factor in your bill is what is actually on your door. Here are realistic fitted prices — part plus labour — for standard working hours in 2026:
One detail that saves a lot of people money: on a uPVC or composite door, you almost never need the whole locking mechanism replaced. In the large majority of cases only the cylinder — the part the key goes into — needs changing, which is the cheaper, faster job. A new mechanism is only necessary when the multipoint strip inside the door has actually broken.
When people say “change all the locks,” they usually mean the external doors — front, back, and any patio or side door. Add those up and the typical total lands around £200 to £350. A small flat with a single door can be done for under £150; a larger house with several doors, or one where you choose anti-snap cylinders throughout, can run past £400. Internal doors are rarely changed for security and are cheaper again.
A good way to keep the cost sensible without cutting corners is to have your cylinders keyed alike — matched so one key opens every external door. A locksmith can usually do this when the cylinders are the same type, and it means changing several locks need not mean carrying several new keys.
This is the question that can cut the bill significantly, and it is worth understanding before you commit. There are two ways to make your old keys stop working:
The honest trade view: if your locks are already good, modern and to standard, rekeying is the smart, economical choice — common when you move into a recently built or well-maintained home. If the locks are old, basic or you simply do not know their history, replacing gives you a known, current standard and is usually the better long-term call. A locksmith can tell you which applies in a couple of minutes on the doorstep.
Four things move a lock-change bill more than anything else. The lock type sets the baseline, as the table above shows. The quality you choose is next — a £15 cylinder and a £60 three-star cylinder fit the same door, and the cheap one is exactly why lock snapping still works as a break-in method. Timing matters: book during normal working hours and you avoid the out-of-hours uplift, which can add fifty per cent or more. And region sets everything else — London and the South East run noticeably higher than the rest of the country.
Watch for the call-out-fee trap. A fair locksmith quotes an all-in price before starting; the ones to avoid advertise a low call-out and then load the bill once they are at your door. Ask for the total, including parts, up front.
Swapping a euro cylinder looks simple on a video, and a confident DIYer can sometimes manage one. But there are two real risks. The first is security: measure the cylinder wrong and it protrudes from the door, handing a burglar the very gap they need to snap it. The second is insurance — many home policies require external locks to meet a recognised standard such as BS3621, and a lock fitted incorrectly, or one that does not meet that standard, can leave a claim disputed. For internal doors, DIY is low-risk. For the doors that actually keep you safe, having it fitted properly is cheap insurance against an expensive mistake.
A named, vetted master locksmith covers your area — no call-out fee.
Cost aside, the moments that genuinely warrant new locks are events rather than dates: moving into a new home, a lost or stolen key, a break-in, the end of a relationship where someone held a key, or a lock that has started sticking and failing. We cover these in detail in when to change your locks, and the single most common one — moving house — has its own guide, because by your first night nobody but you should hold a working key.
However many locks you are changing, the principle is the same: pay for the right standard, get a fixed price first, and have the security-critical doors fitted by someone who does it daily. Done properly, changing your locks is one of the cheapest pieces of peace of mind you will ever buy.
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