Two keys, the same Windows, and sometimes a threefold difference in price. The software is not what changes: what changes is the right of use attached to the key. Here is what the OEM and retail labels actually mean, and how to choose without regret.
The short version
- OEM: cheaper, tied to the first computer it is activated on, not transferable to another machine.
- Retail: more expensive, but it can be moved from one computer to another as long as you stop using it on the previous one.
- In both cases: the same software, the same features, the same security updates. An OEM licence does not give you a cut-down Windows.
The OEM licence: tied to the machine
OEM stands for Original Equipment Manufacturer. This type of licence was originally meant for system builders, who install it on a computer before it is sold. Microsoft’s licence terms attach it to the device on which it is activated for the first time.
In practice, that means:
- Reinstalling Windows on the same computer with the same key: fine, as many times as you need.
- Replacing the drive, the RAM, the graphics card or the power supply: no effect on activation.
- Installing the key on another computer: not permitted, and activation will usually fail.
- Replacing the motherboard: Microsoft treats this as a new computer, except where a faulty board is replaced under warranty by an identical or equivalent model.
That last point deserves a page of its own, and we wrote one: Is Windows tied to the motherboard?
The retail licence: attached to you, not to the hardware
Retail is the licence sold to end users, historically in a box. It is designed to be transferred: you stop using Windows on the old machine, and you activate the key on the new one.
One piece of advice that saves a lot of trouble: when you activate for the first time, sign in with a Microsoft account. The licence is then recorded as a digital licence linked to that account, and the Windows activation troubleshooter lets you reassign it after a hardware change without retyping the key.
Keys tied to a Microsoft account (bind keys)
There is a third arrangement, mostly seen on Office: the key is registered permanently in your Microsoft account. The product then appears in your Microsoft services page and you can reinstall it without keeping the key to hand. It is convenient, but the licence stays attached to that account, so choose from the outset the account you intend to keep. An example from our catalogue: Office 2021 Pro Plus – key tied to a Microsoft account.
Do not confuse this with an “account provided” product, which is a third-party account rather than a key in your name. The difference is explained in our guide Shared account or individual key.
So which one should you buy?
- A laptop or a desktop you intend to keep: OEM. It is the cheapest option, and the restriction will never affect you.
- A custom-built PC you upgrade regularly: retail. The day you swap the motherboard, the licence follows you.
- A computer you plan to sell on with its operating system: OEM is fine, the licence stays with the machine.
- A secondary machine, an old PC brought back into service, a spare workstation: OEM, without hesitation.
- You are not sure: retail. You pay a little more for flexibility you may never need, but you will never be stuck.
To compare directly: Windows 11 Pro as an OEM key and Windows 11 Pro as a retail key, or browse all our Windows licences.
What about Office?
The logic is similar, with one nuance: Office does not depend on the motherboard. Perpetual versions come as a standard retail key, as a key tied to a Microsoft account, as an LTSC edition, and as so-called “phone activation” keys, whose procedure changed at the end of 2025 — see our guide Phone activation for Windows and Office. The full range is in the Microsoft Office category.
How we label this on the site
The licence type is stated in every product title, and the product page spells out what it implies. If anything is still unclear before you order, write to us at support@chkey.ch: we would much rather answer a question before the order than deal with a bad surprise afterwards. CHKey is a Swiss company based in Lausanne, prices are in Swiss francs and a PDF invoice comes with every order. See also our FAQ and the About us page.