SQL Server licensing: per core or server plus CAL
SQL Server offers two licensing models, and the choice between them regularly decides four-figure sums. One counts processor cores and ignores users entirely; the other counts users and ignores hardware. This page shows where the threshold sits and when there is no choice at all.
Which model is cheaper for your user count
The two models price entirely different things. Working out which applies is a short calculation, and it is worth doing before rather than after the purchase.
Server plus CAL
You license the instance and then every user or device that accesses it. Hardware is irrelevant, so a powerful server costs no more than a modest one. This is the cheaper route wherever the group of users is small, known and stable.
Typically cheaper up to roughly 25 to 30 users.
Per core
You license the physical processor cores, with a minimum of four per processor, and the number of users becomes irrelevant. The more people access the database, the better this looks, and above a certain point it is dramatically cheaper.
Typically cheaper above roughly 25 to 30 users.
The case where there is no choice
As soon as an application is reachable from outside the organization, whether a web shop, a customer portal or a supplier interface, the number of people accessing it cannot be determined. Per core licensing is then mandatory, and no user count will satisfy the requirement. The same applies to the Enterprise edition, which is only sold in this form. If you are planning an externally facing application, this decision is made for you and belongs in the budget from the outset.
Standard or Enterprise, and what virtualisation changes
The edition question is easier than the model question, because for most business applications Standard is sufficient. Enterprise is expensive and only pays for itself where its specific capabilities are genuinely used.
Standard
Covers what most line-of-business applications need. Limited in memory and cores per instance, and considerably cheaper for it. For inventory management, accounting and typical industry software it is the right answer.
Enterprise
For large data volumes, high availability and advanced analytics. Available only as per core licensing, at a substantial premium. Worth it only where those capabilities are actually in use rather than nominally available.
Virtual machines
Assigned virtual cores are licensed, again with a minimum of four. Where an entire host environment is virtualised, licensing the host with Enterprise plus Software Assurance can work out cheaper than licensing each guest. It depends on density, so it needs calculating rather than guessing.
Two things that are easy to overlook
First, all physical cores on which the instance can run must be licensed, not just those actually used. Powerful hardware with light utilization is where costings go wrong. Second, downgrade rights matter more here than elsewhere: business applications are frequently certified only for older SQL versions, and the right to run an earlier release is what makes the purchase usable at all. We note what applies for each license.
Frequently asked questions
How many cores must I license?
All physical cores on which the instance can run, with a minimum of four per processor. On virtual machines the assigned virtual cores are counted, again with a minimum of four.
Do I need CALs with per core licensing?
No. Per core licensing covers any number of connections. Client Access Licenses are required only under the server plus CAL model.
What about failover and test systems?
A passive failover instance can be covered under certain conditions; test and development instances generally are not. Describe your setup and we will confirm what is actually needed before you buy.
May I run an older SQL Server version?
Usually yes, through downgrade rights. With SQL Server this comes up often, because business applications are frequently certified only for specific earlier versions.
Is Standard enough for our line-of-business application?
In most cases yes. Enterprise is worth its premium only where large data volumes, high availability or advanced analytics are genuinely in use. Tell us what the database does and we will say so plainly, including when it argues against the larger sale.
Read further
CAL licensing explained
If you choose server plus CAL, this is the other half: user versus device, indirect access and how to count correctly.
Windows Server licensing
SQL Server needs a licensed Windows Server underneath it. Core count rules, minimums and the Standard versus Datacenter threshold.
Used Microsoft licenses
In absolute terms SQL Server is where the gap to the list price is largest, because new licenses here are the most expensive in the range.
We will compare both models for you
Send us your user count and hardware details, and whether the database is reachable from outside. You get both models costed against each other in writing.