How much does it cost to change a cylinder or open a door without a key?

Basic locksmithing is one of the most frequent emergency call-outs for a multi-service technician, and also one of those requiring most care legally, not just technically.

Cylinder: the exact size matters more than the brand

Changing the cylinder replaces the lock's barrel while keeping the rest of the mechanism — the usual solution after losing keys or to improve anti-bumping security. Always measure the exact size of the cylinder (total length and split on each side of the escutcheon) before buying it: a cylinder that is too long or short doesn't fit well and can strain the lock.

Whole lock change: when it goes beyond the cylinder

Replacing the whole lock includes the keep, if the existing recess needs adapting. On home entrance doors, always consider recommending a multi-point security lock over a simple one: the extra cost is far smaller than that of a forced door.

Opening a door without a key: the legal step before the technical one

Before opening a locked door without a key (forgotten, lost or broken), always verify ownership or authorisation for the home or premises, and always try the least invasive method before forcing the lock. Document the service (photo, work report) for your own legal safety — it isn't an optional formality, it's what protects you if any dispute arises afterwards.

Frequently asked questions

Is it worth changing just the cylinder instead of the whole lock? In most cases yes, if the lock and its mechanism are in good condition: it's an effective security upgrade at a much lower cost than replacing it entirely.

Can I open any door without a key if the occupant asks me to? Always verify ownership or authorisation before acting, and document the service — it's legal protection for both the client and the technician.

When is a switch to a multi-point lock needed? On home entrance doors it's advisable from the start: the extra cost compared with a simple lock is far smaller than that of repairing a forced door.

Conclusion

Measuring the cylinder properly before buying it and documenting every opening without a key are the two details that separate a well-done basic locksmith service from one at risk of a claim. Neither costs significant extra time, but both avoid much more expensive problems later.