CapEx vs OpEx in Cloud Computing: What AZ-900 Expects You to Know

AZ-900 · Updated June 2026

CapEx and OpEx describe two ways of spending money on IT. The AZ-900 exam tests this because one of the core reasons organisations move to the cloud is to change how they spend — shifting from large upfront investments to pay-as-you-go consumption. Understanding the difference tells you why cloud matters financially, not just technically.

What CapEx means

CapEx stands for Capital Expenditure. It is money spent on acquiring or improving physical assets that the organisation owns and uses over a long period. In traditional IT, CapEx includes buying servers, storage hardware, networking equipment, and building or leasing datacentres.

The defining characteristics of CapEx are upfront cost, ownership, and depreciation. You pay a large sum at the start, you own the asset, and its value is written off (depreciated) over several years on the balance sheet. A company that buys a rack of servers is making a CapEx investment.

The problem with CapEx in IT is that hardware requirements are hard to predict. You buy for peak capacity, which means the servers sit underutilised most of the time. And by the time the hardware has been depreciated, it may already be outdated.

What OpEx means

OpEx stands for Operational Expenditure. It is money spent on running the business day to day — rent, electricity, staff, software subscriptions, and cloud services. OpEx is expensed immediately on the income statement in the period it is incurred.

Cloud computing is a textbook OpEx model. You do not buy servers. You consume compute, storage, and networking as a metered service and pay a monthly bill based on what you actually used. If your usage drops, your cost drops. If you need more capacity, you scale up without any capital investment.

This is what the AZ-900 exam calls the consumption-based model: you pay for what you use, when you use it, at a predictable rate per unit.

Side by side

Why cloud shifts spending from CapEx to OpEx

In an on-premises setup, an organisation must buy and maintain its own infrastructure. That means forecasting how much compute and storage they will need over the next three to five years and purchasing accordingly — a CapEx-heavy approach. They own every server, pay for the datacentre space, and carry the cost of hardware that sits idle during quiet periods.

In Azure, none of that applies. Microsoft owns the hardware. Microsoft maintains the datacentres. The organisation consumes resources as a service and pays only for what they use. The financial model moves from CapEx to OpEx almost entirely.

• arrow_rightNo upfront purchase of servers or networking equipment.
• arrow_rightNo depreciation schedules to manage on the balance sheet.
• arrow_rightCost scales with actual usage, not with forecasted peak demand.
• arrow_rightInfrastructure upgrades happen automatically — the cloud provider handles hardware generations.

The consumption-based model

AZ-900 introduces the term consumption-based model as part of the cloud concepts domain. It is the OpEx principle applied specifically to cloud pricing. You do not pay for a resource just because it exists — you pay for what you actually consume.

A virtual machine that runs for two hours is billed for two hours. An Azure SQL Database that is paused costs nothing while paused. Storage costs are proportional to how many gigabytes are stored. This is fundamentally different from buying a server that you pay for whether it is running or not.

The consumption-based model also enables better cost planning. Finance teams can look at actual cloud bills and predict future spend based on growth trends, rather than making large multi-year hardware bets.

How to answer CapEx vs OpEx questions on the exam

AZ-900 uses CapEx and OpEx in two types of questions. The first asks you to identify which model a scenario represents. The second asks you to explain a benefit of cloud — and the expected answer often involves moving from CapEx to OpEx.

1. 1

   Identifying the model

   A company purchases 50 servers for a new project. That is CapEx. A company moves to Azure and pays a monthly bill for virtual machines. That is OpEx. Keywords that signal CapEx: buy, purchase, own, depreciate, upfront. Keywords that signal OpEx: subscription, monthly billing, pay-as-you-go, consumption.

2. 2

   Explaining a cloud benefit

   A question asks why an organisation would benefit from migrating to Azure. If the answer choices include "reduces upfront capital expenditure" or "converts fixed costs to variable costs" — those are correct. Moving to cloud eliminates the CapEx of hardware ownership and replaces it with predictable OpEx.

3. 3

   Avoiding the trap

   Azure Reserved Instances and Savings Plans require a one or three year commitment paid upfront. This looks like CapEx but AZ-900 does not test this nuance. At the AZ-900 level, treat all cloud spending as OpEx unless a question explicitly describes a reservation.

How this connects to the broader AZ-900 topics

CapEx vs OpEx sits inside the cloud concepts domain of AZ-900, alongside the benefits of cloud computing. Those benefits — high availability, scalability, elasticity, agility, disaster recovery — are the technical side of the argument. CapEx vs OpEx is the financial side.

The shared responsibility model and IaaS, PaaS, and SaaS also connect here. When you move to SaaS, you hand over the most infrastructure responsibility and shift the most spending to OpEx. With IaaS you keep more control but also keep more infrastructure overhead. PaaS sits in the middle. The less you manage, the more fully OpEx your model becomes.

Frequently asked questions

CapEx and OpEx are simple concepts once you see them as two different answers to the same question: how does the organisation pay for IT? The cloud answer is almost always OpEx — pay for what you use, scale with demand, and let the provider handle the hardware. That shift is one of the fundamental reasons cloud computing exists.

On the exam, watch for financial language in scenario questions. Upfront costs, hardware purchases, and depreciation all point to CapEx. Monthly billing, subscriptions, and consumption all point to OpEx.