Windows Server BYOL decoded

Updated: 22 June 2026

Understand the differences between many Windows Server licensing scenarios in the Cloud. We compare Azure, AWS, Google, and "regular" providers.

Note: new sections are being added to this article. Please bookmark and revisit this page.

Windows Server Core licence requirements

There are the following differences in Core licence requirements in the Cloud:

Dedicated Hosts on Amazon, Google, Alibaba, and Microsoft Azure

When may you assign Windows Server licences to dedicated hosts on Amazon, Google, Alibaba?

You may only assign Windows Server licences to dedicated hosts on Amazon, Google, and Alibaba when:

1. The licences are perpetual and

2. The licences were bought on an agreement signed before October 01, 2019.

When may you assign Windows Server licences to Azure Dedicated Hosts?

Azure is a Listed Provider, so the same pre-October 01, 2019 rules as for Amazon, Google, and Alibaba apply.

In addition, Azure has its own entitlement through Azure Hybrid Benefit. Windows Server Datacenter core licences with active SA or subscription may be allocated to an Azure Dedicated Host, covering all physical cores on the host. Licences assigned to the host cover an unlimited number of VMs, as they do on-premises.

What is a "dedicated host"?

It means that you rent a piece of hardware, and everything that runs on it is yours. The other name is "single-tenant". VMware solutions on big Cloud platforms are always dedicated.

Does Software Assurance renewal or Enterprise Agreement renewal affect BYOL for Windows Server on Amazon, Google, and Alibaba?

It does not. Even if you renewed Software Assurance after October 01, 2019, the only thing that matters is the original purchase date on the perpetual licence or the date of signing of your Enterprise Agreement. This limitation does not apply to Azure, which has its own rules through Azure Hybrid Benefit.

October 01, 2019, and Windows Server BYOL: Explained

On October 01, 2019, Microsoft updated its Product Terms, restricting the right to Bring Your Own Licences to so-called "Listed Providers" to include only products with License Mobility through Software Assurance.

• Windows Server does not have License Mobility through Software Assurance rights.

• Listed Providers are AWS, GCP, Alibaba Cloud, and Azure.

If your perpetual licences or Enterprise Agreement predate October 2019, your Windows Server BYOL rights on AWS, Google, and Alibaba carry over — as long as you stay on Windows Server 2019 or earlier.

Here's the fun part: you won't find any mention of October 01, 2019, in the Product Terms. So, how does it work?

Here's how: there's a concept of "applicable Product Terms" i.e., what terms apply to your agreement and licences.

• When you purchase a licence via an Enterprise Agreement, the applicable Product Terms are the ones from the agreement's effective date: when you signed it.

• The only case in which you must accept the new Product Terms is when you upgrade the product to a version released after the agreement's effective date. In our case, if you upgrade to Windows Server 2022 or later, you must accept its new terms.

• If you signed or renewed your EA before October 01, 2019, the updated Product Terms did not apply to your Windows Server licences, regardless of when you paid for them, even if you paid at the last true-up through September 30, 2022.

• Since we are well past September 30, 2022, it's safe to assume that you renewed your agreement again, at least once. Rest assured, licences originally purchased before or during the term that included October 01, 2019, retain the BYOL rights from before that date and may be used on Listed Providers.

• If you bought your licence online, in retail, or under any other form of agreement: CSP, MPSA, etc, check your agreement and find what Product Terms apply to you.

• If a licence is perpetual without Software Assurance, it's simple: it must have been bought before October 01, 2019.

In any case, make sure you keep your eligible running versions equal to or below Windows Server 2019.

Do I need Software Assurance to assign Windows Server licences to dedicated hosts on Amazon, Google, Alibaba, and Microsoft Azure?

For Amazon, Google, and Alibaba: no. The right to deploy comes from perpetual licences purchased on agreements signed before October 01, 2019. Microsoft removed this right for newer agreements, so only older licences qualify.

In Azure, Azure Hybrid Benefit on Dedicated Hosts requires Windows Server Datacenter licences with active Software Assurance or an active subscription. There is no date restriction.

Windows Server Cross-Edition rights

Microsoft Product Terms and SPUR permit running Windows Server Standard instances under Windows Server Datacenter licences.

Normally, the opposite is not permitted. However, there are two exceptions when Windows Server Standard licences may be assigned to Windows Server Datacenter machines in the Cloud:

1. In Azure via Azure Hybrid Benefit,

2. In a CSP-Hoster environment, in a "License Included" scenario only, i.e. when the CSP-Hoster provides a licence with the virtual machine.

Windows Server Client Access License requirements

There are the following differences between the Windows Server CAL requirements in the Cloud:

RDS CAL requirements

RDS CALs are always required.

If you need help with Windows Server licensing in the Cloud, contact us. We don't sell Microsoft licences or cloud services, so our advice is independent.