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Aqara Smart Lock U400 vs Aqara Smart Lock U600

Full Smart Door Locks comparison in 2026

Updated October 2026
Data from the official Aqara site.
2026 verdict
Among these two Aqara smart locks, the Aqara Smart Lock U600 is the better buy overall, thanks to a longer battery rating, a lower price and the stronger owner rating.
Aqara Smart Lock U600
Winner
Aqara Smart Lock U600
£229.99
Buy on Amazon UK
It brings six ways in, including Apple Home Key and a half-second fingerprint reader, over Matter with Thread, and runs up to ten months on AA batteries. The Aqara Smart Lock U400 answers with something the U600 does not have: ultra-wideband hands-free unlock that opens the door as an iPhone or Apple Watch approaches, plus a rechargeable USB-C battery. The bigger split is form factor, not features: the Aqara Smart Lock U400 is a US deadbolt replacement, while the Aqara Smart Lock U600 is a slim panel made for UK multipoint doors. Pick the U600 for a UK multipoint door or the longest battery life, and the U400 for UWB entry on a standard deadbolt.
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FeatureAqara Smart Lock U400Aqara Smart Lock U600Winner
Price$269.99£229.99Aqara Smart Lock U600
Rating4.14.4Aqara Smart Lock U600
Battery Life6 months10 monthsAqara Smart Lock U600
Weather ResistanceIP65IP65Tie
ConnectivityBluetooth, Thread Protocol, OtherBluetooth, Thread Protocol, OtherTie
IntegrationsGoogle Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, MatterGoogle Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, MatterTie
Lock/Unlock SystemRemote, Bluetooth, Passcode, Fingerprint, NFC Tag, Apple Home Key, Physical KeyRemote, Bluetooth, Passcode, Fingerprint, NFC Tag, Apple Home Key, Physical KeyTie
One-Time PasswordYESYESTie
Periodic PasswordYESYESTie
Emergency FingerprintNONOTie
DoorbellNONOTie

What the differences mean

Door type it fits

The Aqara Smart Lock U400 is a full deadbolt replacement for a standard US front door, with keypad and fingerprint reader on the outside. The Aqara Smart Lock U600 is a slim panel made for UK multipoint doors, where it swaps the handle plates and keeps the door's locking body. Neither fits the other's door, so this is the first thing to check before choosing.

Hands-free unlocking

Only the Aqara Smart Lock U400 carries ultra-wideband, which opens the door as an iPhone or Apple Watch approaches, with no tap. The Aqara Smart Lock U600 has no hands-free option, so you enter with its fingerprint reader, keypad, Apple Home Key, NFC card or mechanical key.

Battery and how you charge it

The Aqara Smart Lock U600 runs up to ten months on four AA batteries. The Aqara Smart Lock U400 uses a built-in rechargeable battery rated around six months, topped up over USB-C, which some owners prefer to buying cells and others find a chore.

Shape and size

The Aqara Smart Lock U600 is a long, slim exterior panel at 335 mm, styled to look like a normal handle set. The Aqara Smart Lock U400 is a compact deadbolt at 178 x 107 x 76 mm and weighs roughly 2 kg. That shape is why the U600 replaces multipoint handle plates.

Which one to buy if

What owners say

Owners of the Aqara Smart Lock U400 single out the ultra-wideband unlock above everything else: the door opens as they walk up with an iPhone or Apple Watch, which several describe as magic and a hit with guests. A fast motor that snaps the deadbolt quicker than their old Schlage or Yale, a rechargeable USB-C battery they can top up from a power bank, and an easy install round out the praise. Not everyone is sold, though: owners complain the housing and battery cover feel plasticky for the price, the HomeKit and Thread setup can be confusing until it clicks, UWB occasionally misses, and Google Home or Alexa need a separate Aqara hub.

Upgrading from the Aqara Smart Lock U400?

Moving from the Aqara Smart Lock U400 to the Aqara Smart Lock U600 is less a straight upgrade than a change of direction. The U600 adds battery life, up to ten months on AA cells against roughly six on the U400's built-in pack, and its UK multipoint panel format, but it gives up the ultra-wideband hands-free unlock that makes the U400 distinctive. If your U400 already opens as you walk up, there is little to gain. The U600 makes sense when you are fitting a UK multipoint door, where the U400 would not fit at all.

Frequently Asked Questions

Which is better overall: Aqara Smart Lock U400 or Aqara Smart Lock U600?

The Aqara Smart Lock U600 is the better buy overall, on longer battery life, a lower price and the stronger owner rating. The Aqara Smart Lock U400 is the one to choose for ultra-wideband hands-free entry on a standard deadbolt. The stronger deciding factor is the door: the U400 fits a US deadbolt, the U600 a UK multipoint door.

What is the biggest difference between the Aqara Smart Lock U400 and the Aqara Smart Lock U600?

The install and the door type. The Aqara Smart Lock U400 is a full deadbolt replacement for a standard US front door, while the Aqara Smart Lock U600 is a slim panel that swaps the handle plates on a UK multipoint door and keeps its locking body. They cover different entry methods too: the U400 adds ultra-wideband hands-free unlock, which the U600 does not have.

Does the Aqara Smart Lock U400 unlock hands-free?

Yes. The Aqara Smart Lock U400 uses ultra-wideband to open as your iPhone or Apple Watch approaches, with no tap. The Aqara Smart Lock U600 has no hands-free mode and is opened with its fingerprint reader, keypad, Apple Home Key, NFC card or key.

Which of these locks is better for a UK multipoint door?

The Aqara Smart Lock U600. It is purpose-built for UK multipoint doors with a 40 to 80 mm thickness, a 72 to 92 mm centre distance and a 35 to 70 mm backset, and it keeps the door's multipoint body. The Aqara Smart Lock U400 is a US deadbolt replacement and would not fit that door.

Who should buy the Aqara Smart Lock U400?

Standard US deadbolt owners, especially Apple households, who want ultra-wideband hands-free unlocking, a fast motor, a rechargeable USB-C battery and Apple Home Key, and who are ready for a slightly fiddly initial HomeKit setup.

Who should buy the Aqara Smart Lock U600?

Anyone with a UK multipoint front door who wants Apple Home Key, a fast fingerprint reader, keypad, NFC and a mechanical key without replacing the door's locking mechanism, and who values up to ten months of battery life on AA cells.

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