Does factory resetting a HomeKit device change the setup code?

No. The setup code is fixed when the accessory is built, and a factory reset does not change it.

The eight-digit HomeKit code, or the eleven-digit Matter one, is printed at the factory and tied to that specific unit for its whole life. A reset does not regenerate it, and there is no menu, in any app, that will. When you reset an accessory and add it back, you use the same code you used the first time.

People usually ask this after resetting a device that was playing up, then realising the sticker is long gone. The hope is that the reset minted a fresh code they can pull up somewhere. It did not. All the reset did was make the accessory advertise itself as unpaired again, ready to accept that same original code.

The one thing that looks like an exception is the short-lived code a platform shows when you share a Matter device to a second app. That code is generated on the spot and expires within minutes. It is not the accessory’s real code, and a reset plays no part in it.

What a factory reset actually clears

A reset wipes the accessory’s state, not its identity. Gone after a reset:

• The HomeKit pairing, so the device drops out of your home along with any automations that used it
• Wi-Fi credentials, on Wi-Fi accessories
• Thread network details, on Thread accessories
• On-device settings and any local schedules

Untouched:

• The setup code
• The serial number and the QR payload printed on the label

That is the point of the code surviving a reset. If it changed, a reset would brick every accessory whose sticker you had lost.

The one case where the code can change

If your “HomeKit device” is actually a software bridge, such as Homebridge, the Home Assistant HomeKit integration, Starling or HOOBS, the rules are different. There the setup code is generated by the software rather than burned into a chip. Wipe the bridge’s stored data or reinstall it and it will usually hand you a new PIN, unless you have fixed one in its configuration.

Physical, shop-bought accessories do not work this way. Their code is hardware.

If the sticker is already gone

A reset will not rescue you here, because you still need the original number to pair the device again. Recovering it is a separate task, covered in finding a lost setup code.

The better fix is upstream. Because the code never changes, you only have to record it once. Back up your setup codes the day each accessory goes in, and a reset becomes a two-minute job rather than a search of the house.