Cloud computing means renting computing resources — servers, storage, networking, software — over the internet instead of owning and running your own hardware. This guide covers the basics properly: the service models, the deployment models, and how "the cloud" actually differs from just having a website or using email.
- What cloud computing actually means
- A brief, useful bit of context
- The three service models: IaaS, PaaS, SaaS
- Deployment models: public, private, hybrid
- Why businesses actually adopt it
- Common misconceptions worth clearing up
- The major providers, briefly
- Once you understand it — what actually matters next
What cloud computing actually means
Cloud computing is the delivery of computing resources — processing power, storage, databases, networking, software — over the internet, from infrastructure owned and operated by a provider, rather than from hardware a business owns and maintains itself. Instead of buying a physical server, installing it in an office cupboard or a rented rack, and maintaining it for years, a business rents equivalent capacity from Microsoft, Amazon or Google, paying for what it uses and scaling that usage up or down as needed.
A brief, useful bit of context
Businesses ran their own physical servers almost exclusively until the mid-2000s, when providers like Amazon began offering rented infrastructure at scale. What made this genuinely transformative wasn't just cheaper hardware access — it was the shift from a large upfront capital cost to a flexible, ongoing operating cost, and the ability to provision new capacity in minutes rather than the weeks or months it took to order, receive and configure physical equipment.
The three service models: IaaS, PaaS, SaaS
Infrastructure as a Service. Rented virtual servers, storage and networking — you manage the operating system and everything above it. Azure VMs and AWS EC2 are examples.
Platform as a Service. A ready-made environment for building and running applications, without managing the underlying servers. Azure App Service is an example.
Software as a Service. Fully finished applications delivered over the internet, with nothing to install or manage. Microsoft 365 is the most obvious example.
Most businesses use a combination of all three, often without thinking about which category a given tool falls into — which is fine day to day, but matters when deciding what actually needs active technical management versus what a vendor handles entirely.
Deployment models: public, private, hybrid
Separately from the service model, there's the question of where that computing infrastructure actually sits. Public cloud means shared infrastructure rented from a provider. Private cloud means infrastructure dedicated to one business alone. Hybrid cloud means a deliberate combination of the two. This is a genuinely important distinction with real commercial and compliance implications — covered in full in our dedicated guide to public, private and hybrid cloud.
Why businesses actually adopt it
- Reduced upfront cost — no large capital outlay on physical hardware
- Elasticity — capacity that scales up or down with actual demand
- Access to specialist tools — advanced databases, AI and analytics that would be prohibitively expensive to build independently
- Business continuity — infrastructure resilience that would be difficult to replicate on a single physical site
- Remote and flexible working — systems accessible from anywhere with an internet connection, not tied to one office location
Common misconceptions worth clearing up
A few beliefs persist that are worth correcting early. Cloud computing does not mean your data is automatically secure — as covered in our guide to cloud security best practices, most of the responsibility for security configuration sits with you, not the provider. Cloud computing does not mean data is automatically backed up in a recoverable sense — platform redundancy protects against provider outages, not against accidental deletion or ransomware, which is a different problem requiring a deliberate backup strategy. And cloud computing is not inherently cheaper than on-premise infrastructure by default — it's cheaper when managed properly, and can become more expensive than expected when it isn't.
The major providers, briefly
Microsoft Azure, Amazon Web Services (AWS) and Google Cloud Platform dominate the market, each with genuine strengths — Azure's tight Microsoft 365 integration, AWS's breadth of services, Google Cloud's data and machine learning tooling. Our full Azure vs AWS vs Google Cloud comparison covers the practical differences in more depth than makes sense to repeat here.
Once you understand it — what actually matters next
Understanding what cloud computing is happens to be the easy part. The genuinely important, ongoing question for any business already using it — which is nearly every business, in some form, whether that's Microsoft 365 or a bespoke application — is whether it's actually being managed properly: monitored, secured, and kept from quietly costing more than it should. That's a different question to "what is cloud computing," and it's the one most worth answering next.
