Is Windows Product Id Unique?

The product ID is not a unique number and it can change on Windows 10 with updates to the operating system.

Are product IDs unique?

Unique product identifiers are assigned to each product by the manufacturer, so if you sell the same product as another retailer, the UPIs will be identical. Common unique product identifiers include Global Trade Item Numbers (GTINs), Manufacturer Part Numbers (MPNs), and brand names.

Is product ID the same as?

No the Product ID is not the same as your Product key. You need a 25 character "Product Key" to activate Windows. The Product ID just identifies which version of Windows you have.