License Management & SAM · Foundations

License metrics explained:
How to distinguish user, device, server, core, and other models

A software licence does more than identify which product may be used. It also defines the unit that must be counted. Only after clarifying whether the basis is users, devices, servers, cores, or consumption can a licence position be assessed reliably.

Updated: 15 August 2026Reading time: about 10 minutesFoundations & practice

In short

The licence metric determines what is counted.

A reliable assessment separates three layers. Only their interaction describes the complete right to use the software.

01Licence metric: Which unit is counted?
02Licence model: How are several rights combined?
03Contract and term: How long does the right apply?

100 licences — but 100 of what?

Do not start with quantity.
Start with the counting logic.

Depending on the vendor and product, the same technical use may be licensed per user, device, server, core, processor, or concurrent access. Cloud and AI services add transactions, credits, and tokens.

01 · Three layers

Metric, model, and term answer different questions

These concepts are often mixed together. Separating them prevents quantities, rights, and cost from resting on the wrong assumption.

WHAT COUNTS?

Licence metric

Which unit is counted?

For example authorised users, devices, servers, cores, concurrent access, or consumption units.

HOW DOES IT WORK?

Licence model

Which rights are combined?

Under Server + CAL, the server and the access by users or devices are both licensed.

FOR HOW LONG?

Contract & term

How long and under which conditions?

For example perpetual, subscription, with maintenance, or consumption-based.

Important:

A subscription is not automatically a licence metric. It may still be priced per user, device, core, or consumption. Subscription first describes time-limited provision, not necessarily the counted unit.

02 · Overview

The most important licence metrics at a glance

The same software can create a completely different cost and risk profile depending on its metric.

Metric	What is counted?	Typical use	Check carefully
User / Named User	Authorised or named people	People work across several devices	User definition, indirect access, unused accounts
Device	Licensed endpoints	Many people share a small number of devices	Inventory, replacement, shared devices
Concurrent User	Highest simultaneous access	Many occasional users	Peak measurement and indirect access
Server / Instance	Physical or virtual servers or instances	Stable server or application estate	Virtualisation, clusters, failover, test systems
Core / vCore	Physical or virtual processor cores	Compute-intensive server products	Minimums, scope, and core packs
Processor / Capacity	Vendor-defined capacity unit	Performance-dependent infrastructure	Factors and full or sub-capacity
CAL / Access	Accessing users or devices	Server + CAL models	Direct and indirect access, external users
Consumption	Actual usage	Cloud, API, and AI services	Unit, price tiers, budgets, limits, anomalies

This overview is a guide. The agreement, Product Terms, and product-specific licence conditions remain authoritative.

03 · User-based licensing

The licence follows the person

A user-based metric counts a named or authorised person. Device allowances remain product-specific. Microsoft 365 Apps, for example, uses user-based subscription licensing by default.

Practical example

An employee works in the office, at home, and on the move using a laptop, tablet, and phone. With a suitable user licence, the authorised person is the primary basis — not every device separately.

Common mistakes

Service or technical accounts are ignored.
Leavers remain licensed.
Inactive is treated as not licensable.
A personal licence is shared between several people.

Remember

An authorised person may require a licence even when use is infrequent. Activity data supports optimisation but does not replace the contractual user definition.

04 · Device-based licensing

The licence follows the device

A device metric licenses the specific endpoint. It can fit shared workplaces in production, care, warehouses, training rooms, or shift operations.

Practical example

Sixty employees work in shifts on 15 terminals. If product and contract offer a device option, the device count may matter more than the number of employees.

Common mistakes

Device replacements are not documented.
Virtual desktops are treated like physical endpoints.
Private or unmanaged devices are missing from scope.
A device option is assumed without contractual availability.

Decision question

Do a few people use many devices, or do many people use a few devices? The answer influences economics, but does not replace a review of product rights.

05 · Concurrent User

The highest simultaneous use is counted

The total authorised population is not decisive; the highest number of simultaneous direct or indirect accesses is. Terms such as Floating User may be used similarly but must not be assumed to mean the same thing.

Practical example

Two hundred people may use a specialist tool, but no more than 35 use it at once. Demand can follow that peak only if the product explicitly permits the metric and concurrency is technically controlled.

Common mistakes

There is no technical measurement or limit.
Indirect access remains invisible.
Peak periods are underestimated.
Concurrent is confused with occasional use.

Remember

Concurrent does not mean unlimited access. Contractual concurrency must be enforced and evidenced.

06 · Server & instance

Deployed infrastructure is counted

The basis may be a physical server, virtual server, installed instance, or managed environment. Even similar terms from one vendor can have different definitions.

Practical example

An application runs on production, test, and a passive recovery system. These may be three deployments unless specific test, disaster-recovery, or failover rights apply.

Common mistakes

VM movement is not assessed for licensing.
Test and passive systems are assumed to be free.
Clusters and failover nodes are missing.
Installed and used are automatically treated as identical.

Remember

An installation, running process, assigned VM, and accessible server can be assessed differently by different vendors.

07 · Core & vCore

Compute capacity is counted — but not always the same kind

The rules may count physical cores, virtual cores, or another capacity unit. Windows Server Standard and Datacenter use Per-Core/CAL; SQL Server may be licensed per core or Server + CAL depending on edition and scenario.

Practical example

A VM has eight vCores on a host with 32 physical cores. Eight vCores alone do not determine the licence quantity. The relevant physical or virtual scope must be established first.

Common mistakes

vCPU, vCore, and physical core are treated as equal.
Minimum licensing is missed.
Core packs are counted as single licences.
Edition virtualisation rights are ignored.

Remember

Core-based does not automatically mean buying the displayed vCPU count. Product, edition, scope, minimums, and rights work together.

08 · Processor, PVU & Capacity

A processor is not always a CPU socket in licence terms

Vendors can define their own capacity units. IBM PVU requirements depend, among other factors, on processor technology and deployed cores, with additional rules for full and eligible sub-capacity.

Practical example

The same hardware can require different licence quantities for two products when vendors apply different factors, tables, or capacity definitions.

Common mistakes

Two CPU sockets are assumed to equal two licences.
Vendor factors are ignored.
Sub-capacity conditions are not met.
Required measurement or reporting tools are missing.

Remember

The vendor definition for the product and agreement matters — not the everyday hardware label.

09 · CAL & Access

The server licence alone may not be enough

Under Server + CAL, the server software and access by users or devices are licensed. For SQL Server Server + CAL, every accessing user or device needs the appropriate CAL.

User CAL or Device CAL?

A User CAL can fit when one person uses several devices. A Device CAL can fit when several people share one device. Availability and economics depend on product, contract, and access pattern.

Common mistakes

Only interactive sign-ins are counted.
Application or interface access remains invisible.
External users and contractors are missing.
Server and access licences are managed separately.

Remember

A technical intermediary does not automatically reduce the number of users or devices that require access rights.

10 · Consumption-based metrics

What is processed or consumed is counted

Cloud and AI services use dynamic units such as transactions, API calls, storage, data volume, compute hours, credits, tokens, actions, or workflows.

Benefit and risk

Cost can follow actual use more closely. Without monitoring, budgets, limits, and ownership, however, consumption can grow faster than expected.

Common mistakes

Only unit price is considered.
Tests, retries, and background processes are absent from forecasts.
Cost is not assigned to a use case or owner.
Usage is measured but quality and business value are not.

Bridge to FinOps

Consumption models require usage, cost, forecast, quality, and business value to be managed continuously together.

11 · Practical comparison

One organisation — five possible counting logics

An organisation wants to provide a business application. The technical reality stays the same, but the available product model changes the measurement basis.

300 generally authorised people
80 shared workplaces
maximum 45 simultaneous accesses
two physical hosts
several virtual servers

Model	Possible starting point
Per User	300 authorised people
Per Device	80 shared devices
Concurrent User	45 simultaneous accesses
Server + CAL	Server licence plus user or device access
Core-based	Relevant physical or virtual cores under the product rules

These figures are not a licence calculation. They only show how strongly counting logic can differ.

01Which option is actually available?
02Who or what is licensable?
03Which minimums and virtualisation rights apply?
04Which evidence must be maintained?

12 · Common misconceptions

Seven statements to test before making a decision

Many incorrect assessments begin with an assumption that sounds plausible but is incomplete.

01
We own 100 licences.
Without the metric, the number says very little.
02
The user was inactive.
Activity and licence liability are not automatically the same.
03
The software runs in a VM.
Some products count the host or impose minimums.
04
Subscription means consumption-based.
A subscription can include a fixed quantity per user, device, or core.
05
Two processors mean two licences.
Vendors may define processors and capacity differently.
06
The application accesses it, not the user.
Indirect access may still be licensable.
07
The tool calculates everything automatically.
Without the right metric, rights, data, and scope, even a strong tool remains incomplete.

13 · Practical checklist

Ask these questions before every licence calculation

This order prevents technical quantities from being calculated before the contractual logic is clear.

01Which product, edition, and version are used?
02Which metric is contractually agreed?
03How does the vendor define user, device, server, core, or consumption?
04Who or what belongs to the licence scope?
05Is access direct, indirect, or automated?
06Is physical or virtual infrastructure assessed?
07Which minimums, packs, or factors apply?
08Which rights cover test, development, failover, and disaster recovery?
09Is the right perpetual, subscription-based, or consumption-based?
10Which data and evidence support the position?
11Who owns contract, technology, budget, and business demand?
12How will growth, architecture, or cloud migration change the metric?

14 · Business value

The right metric is not automatically the one with the smallest number

A lower quantity can be unsuitable when it creates technical restrictions, measurement effort, operational risk, or poor scalability.

DEMAND

Business demand

The metric must fit how people work and the outcome they need.

ARCHITECTURE

Technical reality

Users, devices, virtualisation, and cloud design shape the scope.

CONTROL

Measurability

Evidence, data quality, and ownership must remain manageable.

ECONOMICS

Total cost

Term, flexibility, growth, risk, and operating effort belong in the decision.

The best metric fits the usage scenario, remains controllable, and enables the required business value.

LizenzFrau rule of thumb

Do not start by asking: How many licences do we have?

Ask instead: Which unit counts, which use is permitted, and which technical reality must it cover?

Primary and official sources

Professionally checked and traceable.

This guidance is based on vendor information available on 15 August 2026. The agreement, Product Terms, and product-specific licence conditions remain authoritative.

Note: This article provides accessible professional guidance and is not legal advice. A specific licence position must be assessed against valid agreements, usage rights, and technical deployment.

The licence metric determines what is counted.

Do not start with quantity.Start with the counting logic.

Metric, model, and term answer different questions

Licence metric

Licence model

Contract & term

The most important licence metrics at a glance

The licence follows the person

The licence follows the device

The highest simultaneous use is counted

Deployed infrastructure is counted

Compute capacity is counted — but not always the same kind

A processor is not always a CPU socket in licence terms

The server licence alone may not be enough

What is processed or consumed is counted

One organisation — five possible counting logics

Seven statements to test before making a decision

We own 100 licences.

The user was inactive.

The software runs in a VM.

Subscription means consumption-based.

Two processors mean two licences.

The application accesses it, not the user.

The tool calculates everything automatically.

Ask these questions before every licence calculation

The right metric is not automatically the one with the smallest number

Business demand

Technical reality

Measurability

Total cost

Do not start by asking: How many licences do we have?

Professionally checked and traceable.

License Management & Software Asset Management

Do not start with quantity.
Start with the counting logic.