An End User License Agreement is the contract between you and the software maker that says what you can and cannot do with their program

When you install software — whether it's Microsoft Word, Adobe Photoshop, or a mobile app — you are not buying ownership of the program. You are buying a license, which is permission to use it under specific rules. The End User License Agreement, or EULA, is the document that lists those rules. It tells you whether you can install the software on one computer or five, whether you can share it with family members, whether you can modify it, and what happens if you break the rules.

Most people skip the EULA because it is long, written in legal language, and appears as a wall of text you must scroll through before clicking "I Agree". But the EULA determines what you actually own and what you can legally do with software you paid for. Understanding the main categories — what you can do, what you cannot do, and what the company is not responsible for — helps you know whether the software fits your needs and what risks you are taking on.

Key Takeaways

  • A EULA is a legal contract that grants you permission to use software under specific conditions, not ownership of the software itself.
  • Most EULAs restrict you to installing on a set number of devices, prohibit sharing with others, and forbid reverse-engineering or modifying the code.
  • The company typically disclaims responsibility for data loss, security breaches, or problems caused by the software, even if you paid for it.
  • Violating a EULA can result in your license being revoked, meaning you lose access to the software and your money, with no refund.
  • Some software uses open-source licenses instead, which often allow modification and sharing under different rules than commercial EULAs.

What you can do with software under a typical EULA

A standard EULA grants you the right to install and run the software on a specific number of devices. For personal software like Microsoft Office Home, that is usually one computer. For Microsoft Office 365 (now called Microsoft 365), you can install on up to five devices at once. The EULA also typically allows you to make a backup copy for safety, and to use the software for personal or business purposes — whichever the license covers.

Some EULAs permit you to transfer the license to another person, but only if you uninstall it from all your devices first and give the other person all the materials, including the license key. Others do not allow transfer at all. A few software makers allow limited sharing within a household — for example, Microsoft 365 lets you share your subscription with family members on the same account, and each person gets their own login and storage. But the EULA always specifies exactly how many people can use it and under what conditions.

What you cannot do with software under a typical EULA

A EULA almost always forbids you from sharing your license key with others, even if you are not using the software yourself. It prohibits installing the software on more devices than the license allows. It forbids renting, leasing, or lending the software to someone else. It forbids removing or altering any copyright notices, license keys, or digital locks that protect the software.

Most EULAs also prohibit reverse-engineering — taking apart the code to see how it works or to modify it. They forbid creating derivative works, meaning you cannot use the software as the basis for your own product. They forbid using the software to provide services to others, even if you are not selling it — for example, you cannot use a single-user license of Adobe Photoshop to run a design business. If the software is cloud-based, the EULA typically forbids downloading or copying your data in bulk, or using automated tools to scrape information from the service.

What the software company is not responsible for

Nearly every EULA includes a section called a disclaimer of warranties or limitation of liability. This section says the company is not responsible for certain problems, even if those problems are the company's fault. The most common disclaimers say the software is provided "as is" — meaning the company makes no promise that it will work perfectly, that it will work for your specific needs, or that it will not have bugs.

The company typically disclaims responsibility for data loss, even if the loss is caused by a bug in their software. They disclaim responsibility for security breaches, viruses, or malware that gets into your computer through their software. They disclaim responsibility for lost profits, lost business, or other indirect damage caused by the software failing. In many cases, the company's total liability is capped at the amount you paid for the software — so if you paid $50 for a program that destroys $5,000 worth of work, you can recover at most $50.

These disclaimers are enforceable in most jurisdictions, though some places (like the European Union) limit how much a company can disclaim responsibility for intentional harm or gross negligence. But for ordinary bugs and failures, the disclaimer usually holds up in court.

What happens if you violate the EULA

If you break the terms of a EULA — for example, by sharing your license key with someone else, or by installing the software on more devices than allowed — the software company can revoke your license. When a license is revoked, you lose access to the software immediately. If the software is cloud-based (like Microsoft 365 or Adobe Creative Cloud), you may lose access to files stored in the cloud. If the software is installed on your computer, it may stop working or display a message saying your license is invalid.

In most cases, you do not get a refund when your license is revoked. The company's terms typically state that violation of the EULA forfeits your right to a refund. Some companies issue warnings before revoking a license, but they are not required to do so. In rare cases, particularly egregious violations — such as using software you know is pirated, or using a license key you did not purchase — can result in legal action by the company against you, though this is uncommon for individual users.

How EULAs differ from open-source licenses

Not all software is governed by a traditional EULA. Open-source software — programs whose source code is publicly available — typically uses a different kind of license, such as the GNU General Public License (GPL), the MIT License, or the Apache License. These licenses often allow you to modify the software, share it with others, and even use it in your own products, as long as you follow specific rules (such as crediting the original author or sharing your modifications).

Open-source licenses are more permissive than typical EULAs, but they come with their own restrictions and responsibilities. For example, the GPL requires that if you modify open-source software and distribute it, you must make your modifications available to others under the same GPL license. Open-source software is often free, but "free" refers to freedom to modify and share, not necessarily to price. Some open-source projects accept donations or charge for support, even though the software itself is free to use.

Reading a EULA before you buy or install

Most software vendors make the EULA available before you purchase or install. On a website, you can usually find it in a link labeled "Terms of Service", "License Agreement", or "EULA". In an app store like Apple's App Store or Google Play, you can often view the developer's terms by scrolling down on the app's page. When you download software from a vendor's website, the EULA usually appears during installation, and you must check a box saying you agree before proceeding.

If you want to understand the EULA without reading every word, focus on three sections: the grant of license (what you are allowed to do), the restrictions (what you are not allowed to do), and the disclaimer of liability (what the company is not responsible for). If any of these sections conflict with how you plan to use the software, that software may not be right for you. Some vendors offer different license tiers — for example, a personal license and a business license — so you may be able to purchase a license that matches your needs instead of accepting restrictions you do not want.

Frequently Asked Questions

Can I use software I bought on one computer on a different computer?

It depends on the EULA. Most single-user licenses allow you to install on one computer at a time, and you can move the license to a different computer if you uninstall it from the old one. Some licenses are tied to a specific computer and cannot be moved. Subscription software like Microsoft 365 typically allows you to install on multiple devices (usually up to five) simultaneously. Check the EULA or the product page to see how many devices your specific license covers.

If I buy software, do I own it?

No. When you buy software, you are purchasing a license to use it, not ownership of the software itself. The software company retains ownership of the code. Your license can be revoked if you violate the EULA, and you cannot legally sell or give away the software to someone else (though some EULAs do permit license transfer under specific conditions). This is different from buying a physical book or a car, which you own outright.

What does "as is" mean in a EULA?

It means the software company makes no may provide that the software will work, that it will work for your specific purpose, or that it will not have bugs. The company is saying they are providing the software in its current condition, and you are accepting it with all its flaws. This clause protects the company from being sued if the software crashes, loses your data, or does not do what you expected.

Can I modify software I bought?

Almost never, under a standard EULA. Most commercial software licenses explicitly forbid modifying the code or reverse-engineering it to see how it works. Open-source software often permits modification, but usually requires you to share your changes with others under the same license. Check the EULA or license document to see whether modification is allowed.

What happens if I share my license key with a friend?

You are violating the EULA. The software company can revoke both your license and your friend's access to the software. You will likely lose your money with no refund. In some cases, the company may take legal action, though this is rare for individuals. Most software companies use activation systems that detect when a license key is being used on too many devices or by multiple people simultaneously and will disable it.