SQL Server licensing confuses buyers because the same edition can be licensed in two different ways. The right choice depends on how many people or devices will use the database. This guide explains both models and gives a simple rule for choosing.
How-To & Comparisons
SQL Server Licensing: Per Core vs Server + CAL
The two ways to license SQL Server Standard and Enterprise (per core or Server + CAL), the 4-core minimum, and how to choose.
Written by Sujeet Kumar, with 12 years of experience at DigitalKeyWorld.
Direct Answer
SQL Server is licensed in two ways: per core (every physical or virtual core running SQL Server needs a license, with a minimum of 4 per processor) or Server + CAL (one server license plus a CAL for each user or device, available for Standard edition). Per core suits many users or internet-facing apps; Server + CAL suits a small, known group of users.
The two SQL Server licensing models
SQL Server Standard can be licensed per core or with a server license plus CALs. SQL Server Enterprise is licensed per core only. The model decides what you count: processor cores in one case, and users or devices in the other.
Per-core licensing
With per-core licensing, you license every core that runs SQL Server. The minimum is four core licenses per physical processor or per virtual machine, and core licenses are sold in packs of two. Any number of users can then connect, including external users and web apps, so it fits public websites and large user groups. Browse the options in SQL Server license keys.
Server + CAL licensing
With Server + CAL, you buy one server license and one Client Access License per user or per device that connects. It is available for Standard edition only. It suits an internal system with a small, fixed group of users, such as an office accounting app. If the number of users grows or the app is exposed to the public, the CAL count becomes impractical.
How to choose between them
| Situation | Better model |
|---|---|
| Public website or app with unknown users | Per core |
| Large or growing number of users | Per core |
| Fewer than a few dozen known users, internal only | Server + CAL |
| Enterprise edition features needed | Per core (the only option) |
Standard vs Enterprise vs the free editions
Standard covers most business databases. Enterprise adds high-end features for large systems. Express is free with size limits, and Developer is free for development and testing, not production. A full comparison is in SQL Server Editions Explained, and you can follow the steps in How to activate SQL Server after you buy. Compare with the server side of licensing in Windows Server CALs explained.
Frequently asked questions
What is the minimum number of core licenses for SQL Server?
Four core licenses per physical processor or per virtual machine, even if it has fewer cores. Core licenses are sold in packs of two.
Can SQL Server Enterprise be licensed with Server + CAL?
No. Enterprise edition is licensed per core. Server + CAL is available for Standard edition.
Is SQL Server Express free?
Yes. Express is a free edition with size and feature limits, suited to small apps and learning.
Pro Tip
Count the people or devices that will connect before you choose. If the number is small and fixed, Server + CAL is often cheaper; if it is large or unknown, per core is simpler.
Sources & References
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