Nuki cylinder: keep yours or buy the Universal Cylinder?

The Go and Pro sit on the inside of your existing lock cylinder, the Ultra replaces it with Nuki's own. What matters is the emergency function – and whether your current cylinder has it. Here is when you need the Nuki Universal Cylinder, what it costs and how to check your door. Details and prices from nuki.io and the Nuki help centre, as of 18 October 2026.

	Your existing cylinder	Nuki Universal Cylinder	Smart Lock Ultra
Price on nuki.io	€0 – you keep it	€99	Included in the Ultra (€369)
Works with	Smart Lock Go, Pro (5th gen) and earlier generations	Smart Lock Go and 2nd–4th generation – not the Pro (5th gen)	Built in – the cylinder must be swapped
Emergency function	Recommended – check it yourself (see below)	Yes	Yes
Security	Depends on your cylinder	SKG***, EN 1303, protection against drilling, impact and core pulling	SKG***, EN 1303 and DIN 18252, drill-resistant housing
Sizes	Fits as it is	Outside 30–55 mm, inside 30–67.5 mm in 2.5 mm steps – 96 combinations, modular	Universal Cylinder sizes
Keys	Your current keys	3 reversible keys, more via the M&C shop with the Security Card	3 new keys
With 10% off	Go €134.10 / Pro €251.10	€99 alone is below €149 – Go + cylinder €248 → €223.20	€332.10

Sources: product pages for the Universal Cylinder and Smart Lock Ultra on nuki.io; Nuki help centre article on the emergency function (18 October 2026).

What to check

The emergency function is what matters. The Go and Pro are mounted on the inside over your key, which stays in the lock. A cylinder with an emergency and hazard function (Not- und Gefahrenfunktion) still lets you unlock from outside with a second key even though a key is inserted inside. Without it, the outside key won't turn while Nuki holds the inside one.

How to test your cylinder. Nuki's check: put a key in on the inside of the door and turn it at an angle, then insert a second key from outside. If you can lock with the outside key, your cylinder has the emergency function and you can keep it.

No emergency function? Retrofit or swap. Many cylinders can be retrofitted – ask a locksmith. Euro profile cylinders are standardised and easy to replace; the Nuki Universal Cylinder (€99) is made for Nuki smart locks, comes with 3 reversible keys and is rated SKG***, the highest class against drilling, impact and core pulling.

Which lock takes which cylinder. The Universal Cylinder fits the Smart Lock Go and the 2nd to 4th generation. The Smart Lock Pro (5th gen) is not compatible with it – it keeps your existing cylinder. The Ultra always comes with its own Universal Cylinder, so you swap the cylinder when installing it.

Measure before you buy. The Universal Cylinder is modular: 6 outside lengths from 30 to 55 mm and 16 inside lengths from 30 to 67.5 mm, 96 combinations in total – enough for almost every door in Europe. Half cylinders (for cabinets) are not supported. Extra keys and keyed-alike cylinders are ordered from M&C with the Nuki Security Card, which stops unauthorised copies.

Which lock suits your door is in our Go vs Pro vs Ultra comparison.

Frequently asked questions

Do I need a new cylinder for a Nuki smart lock?

Not necessarily. The Go and Pro work with your existing cylinder; Nuki recommends one with an emergency and hazard function. Only the Ultra requires a cylinder swap, and it comes with the Universal Cylinder (nuki.io, 18 October 2026).

What is the emergency and hazard function?

It lets you unlock the door from outside with a key even when a key is inserted on the inside – the inner and outer keys turn in sync. Because Nuki holds the inside key, it is what keeps your physical key working from outside.

What does the Nuki Universal Cylinder cost?

€99 in the official Nuki shop, with 3 keys (18 October 2026). With the Smart Lock Ultra it is included.

Does the Universal Cylinder fit the Smart Lock Pro (5th gen)?

No. According to Nuki it works with the Smart Lock Go and the 2nd to 4th generation; the Pro (5th gen) keeps your existing cylinder.

Which sizes does the Universal Cylinder come in?

It is modular: 30–55 mm outside and 30–67.5 mm inside in 2.5 mm steps, 96 combinations in total.

How secure is the Universal Cylinder?

It was developed with M&C and is rated SKG***, the highest class, and certified to EN 1303, with protection against drilling, impact and core pulling.

Does the Nuki discount code work on the cylinder?

Our code gives new customers 10% off orders over €149 in the official Nuki shop. The cylinder (€99) alone is below that; with a Smart Lock Go the order is €248 and costs €223.20.

Our take

Test your cylinder first – if the outside key turns with a key inside, a Go (€149) or Pro (€279) goes on without new hardware. If it fails, a Go with the Universal Cylinder costs €248, or €223.20 with our code; the Ultra (€369) already includes the cylinder. On the Pro (5th gen) the Universal Cylinder does not fit, so retrofit your cylinder with a locksmith instead.

10% off your Nuki

New customers get 10% off orders over €149 in the official Nuki shop with our Nuki discount code – a Smart Lock Go with the Universal Cylinder then costs €223.20 instead of €248, the Ultra with its cylinder €332.10 instead of €369.

Get the discount code →

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