Cloud computing is the delivery of computing power, data storage and software over the internet, on demand, from huge data centers run by providers such as Amazon Web Services, Microsoft Azure and Google Cloud. Instead of buying and maintaining their own servers, people and businesses rent what they need and pay for what they use, the same way a home pays for electricity rather than running its own power plant.

What is cloud computing, in simple terms?

Every time you stream a show, back up photos from your phone, or open a shared document, you are using the cloud. The files and programs are not stored on your device; they live on servers in a data center somewhere, and your device reaches them over the internet.

The U.S. National Institute of Standards and Technology defines cloud computing by five features, which remain the standard description:

• On-demand self-service: you can set up computing resources yourself, in minutes, without calling the provider.
• Broad network access: services are reached over the internet from phones, laptops and other devices.
• Resource pooling: the provider shares the same physical hardware among many customers, kept separate by software.
• Rapid elasticity: capacity can grow or shrink quickly to match demand, such as a retailer's website on Black Friday.
• Measured service: usage is metered, so customers pay for what they actually use.

The physical side of all this is a network of large, power-hungry buildings full of servers and cooling equipment. Our explainer on the hidden buildings that run the internet looks at those data centers in more detail.

What are the three types of cloud computing?

Cloud services are usually grouped into three layers, depending on how much the provider manages for you.

A useful way to remember the difference is a pizza analogy: IaaS is renting a kitchen, PaaS is ordering a take-and-bake pizza, and SaaS is having pizza delivered ready to eat.

There is also a second way of classifying cloud setups, by where the computing lives:

• Public cloud: shared infrastructure owned by a provider such as AWS, used by many customers.
• Private cloud: cloud-style infrastructure dedicated to a single organization, often in its own data center.
• Hybrid cloud: a mix of the two, common in banks, hospitals and government agencies that keep sensitive data on their own systems.
• Multicloud: using more than one public provider, often to avoid depending on a single company.

Who are the biggest cloud providers?

Three companies dominate. In the second quarter of 2026, according to Synergy Research Group, worldwide spending on cloud infrastructure services reached about $143 billion, up 43% from a year earlier, the fastest growth in eight years. Revenue over the previous 12 months came to roughly $500 billion.

AWS is still the largest, but its share has slipped as Microsoft and Google grow faster. The biggest change in the market is artificial intelligence: training and running AI models requires enormous numbers of specialized chips, and most companies rent that capacity rather than buy it. Synergy counts nine "neocloud" companies, specialists that mainly rent out GPU capacity for AI, among the 40 largest cloud providers. The United States is by far the largest cloud market.

What are the benefits and drawbacks of cloud computing?

Cloud computing is now the default for most new software, but it is not the right fit for everything.

• Pro: lower upfront cost. No need to buy servers before you know how much you'll use.
• Pro: scalability. Capacity can grow with demand and shrink when it's not needed.
• Pro: speed. New services can be launched in minutes rather than weeks.
• Pro: reliability and backup. Data can be copied across several locations, protecting against hardware failure or local disasters.
• Con: ongoing costs can climb. Bills grow with usage, and companies running steady, heavy workloads sometimes find their own hardware cheaper.
• Con: dependence on a provider. Outages at a major provider can take down thousands of websites at once, and moving between providers can be difficult.
• Con: security and privacy responsibilities. Providers secure the infrastructure, but customers must configure their own systems correctly, and misconfigured storage is a common cause of data leaks.

How much does cloud computing cost?

Cloud pricing is usage-based, so the cost depends on what you run and for how long. For individuals, cloud storage plans for photos and files typically cost a few dollars a month, and many come with a free tier. For businesses, bills are made up of several meters running at once:

• Compute: charged by the second or hour for each virtual server, with higher prices for more powerful machines and specialized AI chips.
• Storage: charged per gigabyte stored per month, with cheaper rates for data that is rarely accessed.
• Data transfer: moving data out of a provider's network to the internet is usually charged, while moving it in is often free.
• Managed services: databases, AI models and other ready-made services carry their own pricing.

All three major providers offer free tiers and starter credits, which is how most learners practice without spending money. Companies cut costs by switching off unused resources, committing to one- or three-year usage in exchange for discounts, and choosing cheaper storage classes for old data.

What does a cloud computing job do?

Cloud professionals design, build, run and secure the systems that companies host in the cloud. Common roles include:

• Cloud engineer or administrator: sets up and maintains servers, storage, networks and user access, and fixes problems when they occur.
• Cloud architect: designs how an organization's systems fit together in the cloud, balancing cost, performance and security.
• DevOps or platform engineer: automates how software is built, tested and released, often using code to define infrastructure.
• Cloud security specialist: protects cloud systems and data; this overlaps heavily with cyber security careers.
• Cloud data or AI engineer: builds data pipelines and runs machine learning workloads on cloud platforms.

A typical day might involve moving an older company application onto a cloud platform, tuning costs so the business is not paying for idle servers, responding to an outage alert, or reviewing access permissions. Pay is generally well above average. The Bureau of Labor Statistics groups many senior cloud roles with computer network architects, an occupation that pays well into six figures at the median.

Can I learn cloud computing in 3 months?

Yes, you can learn the fundamentals in about three months, but becoming job-ready usually takes longer. With steady study of five to ten hours a week, a beginner can typically:

1. Weeks 1-4: learn core ideas such as virtual machines, storage, networking, regions, and the shared responsibility model for security.
2. Weeks 5-8: pick one provider, usually AWS, Azure or Google Cloud, and build small hands-on projects such as hosting a website or setting up storage with access controls.
3. Weeks 9-12: prepare for and take an entry-level certification such as AWS Certified Cloud Practitioner, Microsoft Azure Fundamentals (AZ-900) or Google Cloud Digital Leader.

An entry-level certificate shows employers you understand the basics, but most hiring managers look for practical experience. People who reach their first cloud job quickly usually already have some IT, networking or programming background, or keep building projects for several more months after their first certificate.

Is cloud computing hard to learn?

The basics are not especially hard, and you do not need a computer science degree to start. The difficulty rises at the professional level, where you need to understand networking, Linux, security, scripting and how real systems fail. The broad range of services each provider offers, hundreds in the case of AWS, can feel overwhelming, so most learners focus on the core services first and add specialist areas later.

Where things stand in October 2026

The cloud market is growing faster than at any time since 2018, driven by demand for AI computing. AWS, Microsoft and Google together hold about 63% of the market, with Google gaining share and specialist AI cloud providers growing quickly. For learners, entry-level certifications remain a common first step, and cloud skills continue to be among the most in-demand in tech hiring. See our cloud computing reference page for related terms.

Frequently asked questions

Is the cloud just someone else's computer?

Essentially, yes. Your data and programs run on servers owned by a provider, but cloud platforms add automation, scaling, backup and security tools that a single rented server would not have.

Is my data safe in the cloud?

Major providers invest heavily in physical and digital security, often more than a small business could. Most cloud data breaches come from customer mistakes, such as weak passwords or storage left open to the public, rather than failures by the provider.

What is the difference between cloud storage and cloud computing?

Cloud storage, such as Google Drive or iCloud, is one kind of cloud service. Cloud computing is the broader category that also includes running applications, databases and AI models.

Which cloud platform should I learn first?

AWS has the largest market share and the most job listings, Azure is common in companies that already use Microsoft products, and Google Cloud is strong in data and AI. Many learners start with AWS, but the core concepts transfer between all three.

Do I need to know coding to work in the cloud?

Not for entry-level roles, but basic scripting in a language such as Python, along with command-line skills, becomes important as you move into engineering roles.