Windows Server and CAL licences for your company's server

With Windows Server you pay twice: once for the server, and again for the people who connect to it.

The server is licensed per core (from the 2016 version on). You count every physical core in the processors, with a minimum of 8 cores per processor and 16 per server. Licences come in packs of 2 or 16 cores. Example: a server with one 6-core processor is still licensed as 16 cores, which means eight 2-core packs or one 16-core pack.

The edition decides how many virtual machines you can run. Standard gives you the right to 2 virtual machines on a fully licensed server; for 2 more, you license all the cores again. Datacenter allows unlimited virtual machines. For a handful of virtual machines Standard usually works out cheaper; when you run many, price up Datacenter too. Tell us how many you run and we'll do the sums.

Every person or device that uses the server needs an access licence (CAL). A User CAL covers one person, on any number of devices. A Device CAL covers one device, however many people work on it, such as a computer used across three shifts. If people work on the server through Remote Desktop, each of them also needs an RDS CAL on top of the standard CAL. The CAL version must be at least the server version: a 2022 CAL works with Windows Server 2022, 2019 and older.

Access from outside the company (customers, partners) is covered by the External Connector: one licence per server, for any number of external users.

CAL suites bundle several access licences into one: the Core CAL Suite includes the Windows Server CAL and the Standard CALs for Exchange, SharePoint and Skype for Business; the Enterprise CAL Suite adds the Enterprise CALs for the same products. The Core Infrastructure Server Suite (CIS) combines Windows Server and System Center, also licensed per core.

Versions 2008 R2, 2012 and 2012 R2 were licensed differently: per server or per processor. Their product pages spell it out.