You can only install it on one computer. If you need to upgrade an additional computer to Windows 10 Pro, you need an additional license. Click the $99 button to make your purchase (the price might vary by region or depending on the edition you are upgrading from or upgrading to).
What happens if I use the same Windows 10 key on two computers?
Windows product keys can only be activated on one computer at a time. That means you'll have to deactivate one end in order to get another to work.
Can you use the same Windows license on two computers?
Can 2 computers use the same Windows product key on multiple?
No, the key which can be used with either 32 or 64 bit Windows 7 is only intended for use with 1 of the disk. You cannot use it to install both.
Can I use Windows 10 pro key on 2 computers?
You can have 2 computers on the same Microsoft Account. You can even sync settings between them or turn sync off for devices on the same account.