Nuki Calibration Failed — How to Fix Setup Errors

What it means

A Nuki calibration failed error means the lock could not learn its lock and unlock end positions.
The most common causes are an outside key blocking rotation, a sticking cylinder, or door misalignment.

Affected Models

Nuki Smart Lock 3.0
Nuki Smart Lock 3.0 Pro
Nuki Smart Lock 4.0 Pro
Nuki Smart Lock 4th Generation

Common Causes

Outside key inserted in the cylinder, blocking rotation
Sticking euro cylinder needing lubrication
Door or strike misalignment
Nuki not securely clamped on the cylinder thumb-turn
Battery low — calibration needs full motor torque

How to Fix It

Remove the outside key.

If a key is left in the cylinder from the outside, Nuki cannot turn the cylinder.
Remove the outside key before running calibration.
Test the cylinder by hand.

Use the inside thumb-turn or a key from outside to operate the deadbolt manually.
It should turn smoothly.
If it sticks, lubricate with graphite or dry PTFE — no oil-based products.
Verify Nuki is securely mounted.

Make sure Nuki is firmly clamped on the cylinder's thumb-turn knob.
A loose Nuki spins or slips during calibration.
Tighten the clamp screws to spec.
Replace the batteries.

Even slightly weak batteries can fail calibration because the motor may stall under load.
Fit fresh batteries (CR123A on most Nuki models, AA on 4.0 Pro).
Run calibration with the door closed.

Some Nuki users find calibration succeeds with the door closed (so the bolt actually engages the strike) where it fails open.
Close the door before starting the calibration sequence.

When to Call a Professional

If the cylinder is good, alignment is good, and Nuki still fails calibration, Nuki support can advise.
The lock may be incompatible with very unusual cylinder profiles.

Frequently Asked Questions

Why does Nuki calibration fail if I have a thumb-turn on the outside?

Nuki cannot turn a freewheeling cylinder. If you have a thumb-turn (rather than a key cylinder) on the outside, the cylinder spins independently of the inside thumb-turn — Nuki has nothing to grip on. You need a key cylinder on the outside.

Does my euro cylinder need to stick out a certain amount for Nuki to fit?

Yes. Nuki requires the inside cylinder to protrude correctly so Nuki can clamp on the thumb-turn. Cylinders that are too short or too long need to be replaced for Nuki to mount and calibrate properly.