Identify your lock

Answer five questions about the door in front of you. The wizard narrows down the lock family, then tells you exactly what to measure and which retrofit architectures fit.

Nothing you answer is uploaded anywhere — it runs in your browser.

If you would rather do it by hand

The order below is the one a locksmith uses, because each answer makes the next one faster.

1. Where does the key go? Into a removable cylinder, or into a keyhole cut in the lock case itself? A removable cylinder means a euro, oval or Scandinavian profile. A keyhole in the faceplate with no separate cylinder means a lever lock — usually British.
2. What does the inside control look like? A round thumb-turn, a lever, a knob, a slide, or a tall push-pull bar. This is what any retrofit motor has to drive, so it is the most important shape on the door.
3. Do you have to lift the handle to lock it? If yes, it is a multipoint system, and any retrofit has to cope with several turns of the cylinder, not one.
4. Backset — door edge to the centre of the keyhole. 55 and 60 mm mean continental Europe. 64 mm means Japan. 2-3/4 in (70 mm) means North America.
5. Centre distance — spindle centre to cylinder centre. 72 mm is a European interior door, 92 mm a European exterior door. This number decides whether a handle fits at all.

Then take the measurements on the measuring guide in the order listed for your lock family.

What the wizard cannot do

It cannot see your door. It works from the answers you give it, so if two options both seem true, pick the one you are more sure of and check the measurement table on the resulting page — the numbers will confirm or rule it out.

If the wizard gets it wrong, that is a bug in the decision data, not in your door. Tell us which answer led you astray and the tree gets fixed for everyone.

Questions

Can I identify my lock from a photo alone? Not reliably yet, and not on a static site. The Kitemark on a British lock faceplate or the star marking on a cylinder can be read from a close photo, but backset and centre distance need a physical measurement. The photo tool on this site helps you measure; the identification comes from the numbers.

What if my lock matches nothing here? Then it is probably one of the regional families we have not catalogued yet — most likely African, South American, Indian or Middle Eastern. Take the backset, the centre distance and the faceplate size, and open an issue with a photo. That is exactly the contribution this site needs.

Why does the wizard ask about my country? Because lock standards follow the market the hardware was sold into, and the same 55 mm backset means different things in Germany and in an imported door elsewhere. It is a hint, not a rule — the measurements always win.