How many licences
do you actually need?

Windows Server 2025 is licensed per physical core, in 2-core packs, with two floors: at least 8 core licences per processor and at least 16 per server. So a 2×16-core host needs 32 core licences (16 × 2-core packs). Datacenter covers unlimited VMs on that host; Standard covers 2 VMs (OSEs) per full set of core licences and stacks — 6 VMs on that host = 32 cores × 3 = 96 Standard core licences. CALs are always separate. The calculator applies both minimums and the Standard stacking for you.

They license the same physical cores; the difference is virtualisation rights. Standard grants 2 operating system environments (VMs) per full set of core licences and can be stacked for more; Datacenter grants unlimited VMs on the licensed host and adds features like Storage Spaces Direct and Software Defined Networking. As VM density rises, Datacenter needs fewer licences — but which is cheaper depends on the prices you are quoted, so this tool shows the counts for both and lets a specialist price the crossover rather than guessing it.

Yes. Every user or device that accesses a Windows Server needs a Windows Server CAL, bought separately from the server licence — you pick the cheaper axis (User or Device) and can mix across the organisation. If users connect to a Windows Server session host (Remote Desktop Services), they also need an RDS CAL on top: RDS CALs are additive, never a substitute for the base CAL. Windows 10/11 multi-session on Azure Virtual Desktop does not need an RDS CAL.

Correct — that is a widely repeated myth. SQL Server 2022 per-core licensing has only a 4-core-per-processor minimum (and 4 cores per VM when you license individual VMs). There is no per-server minimum. A single-socket 6-core box needs 6 core licences (3 × 2-core packs), not 16. Enterprise edition is per-core only; Standard can be per-core or Server+CAL, whichever is cheaper for your user count. This calculator uses the correct 4-core floor and flags where SA changes your options.

VMware is now sold as an annual per-core subscription (VCF, VVF, vSphere Standard or Enterprise Plus), with a 16-core-per-CPU minimum. You license every physical core in each populated socket — including cores disabled in the BIOS. So three hosts with 2×24-core CPUs = 3 × 48 = 144 core subscriptions per year. A "72-core minimum per order" is sometimes quoted; it is not in the program terms we can verify, so the calculator leaves it off by default and flags it as something to confirm with us before ordering.

No. Microsoft and VMware pricing depends on your agreement (CSP, Enterprise Agreement, MPSA, Broadcom portal), region, term and Software Assurance status, and reseller pricing is confidential — so a public price would mislead. The tool counts the licences you need and shows exactly how it counted them; a Servnet licensing specialist then confirms the counts and returns firm UK pricing, including finance if you want to spread it.

Software Assurance (SA) is an add-on that grants version upgrade rights, licence mobility between hosts, and — for SQL Server — unlimited passive/failover replicas at no extra licence cost. It matters most when you license SQL per individual VM (which requires SA for mobility), when you move workloads between hosts, or when you want free disaster-recovery replicas. The calculator gates the SA-only options so the default never under-licenses.

The maths is deterministic and covered by an automated test suite, and every rule is verified against a primary Microsoft or Broadcom source (linked on the page and dated). Licensing terms do change — the VMware program documentation is reviewed monthly and Microsoft Product Terms quarterly — so the counts are indicative planning figures that a specialist confirms before you buy. Edge cases (SPLA hosting, mixed clusters, embedded/OEM, non-profit or education pricing) are flagged rather than guessed.