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What Is Adware?

If you’re getting a ton of pop-ups that slow down your computer, your device
may be infected with adware.

All of our content is written by humans, not robots. Learn More
Aliza Vigderman
Gabe TurnerChief Editor
Last Updated Mar 13, 2024
By Aliza Vigderman & Gabe Turner on Mar 13, 2024

There’s nothing worse than being interrupted by pop-up ads when you’re browsing online. From offers to make seven figures while sitting on your couch to amazing weight loss programs, these ads are annoying, illegitimate, and just plain distracting. They might also be adware. What is adware, you say? Let’s get into it!

Adware: What It Is and How to Stop It

Adware is a piece of software that downloads advertising material into your device without your knowledge. The ads are often benign, but the way they are brought to you is morally questionable. The good news is you can stop adware simply by using antivirus software. Antivirus software can not only stop the process of downloading advertising material without your permission, but also get rid of the offending software. Here are the best antiviruses we’ve tested:

Editor's Rating:
9.7 /10
Editor's Rating:
8.9 /10
Editor's Rating:
9.5 /10

Who Does Adware Target?

Adware targets both individuals and businesses, but it targets individuals more commonly, often by offering new games, movies, or deals that turn out to be fraudulent.1 You know the saying — if something seems too good to be true, it probably is.


How Adware Spreads

Adware usually spreads in one of two ways:

  • Users download a free program (called freeware or shareware) that they don’t know contains adware.
  • Users go to websites infected with adware that takes advantage of vulnerabilities within browsers, downloading adware in files.

What Adware Does

Adware generates revenue through online advertising. However, unlike with regular advertisements, users download adware unknowingly. Aside from the ads themselves, adware can track what websites users visit to create even more targeted ads. Some adware sells this data to third parties as well. Think of it as the circle of life, but for creepy online advertisements.

Is Adware a Virus?

There’s a common misconception that adware is a type of virus, but that’s not the case. Rather, adware is a potentially unwanted program, abbreviated (adorably) as PUP.

Types of Adware

Adware is not all created equal. There are different types of it, including these:

  • Legitimate adware: Legitimate adware is any online advertisement that doesn’t contain malware (no matter how annoying it may be).
  • PUPs: Potentially unwanted programs are any software that you didn’t ask to be installed on your device.2
  • Browser hijackers: Browser hijackers change your browser settings without your knowledge or consent, typically affecting both homepage and default search settings.
  • Device-specific: Different devices and operating systems have different types of adware, so adware for Macs may look different from adware for Windows computers.

Adware vs. Spyware vs. Malware vs. PUP vs. PUA

With so many abbreviations, the differences between PUP, PUA, and the like can get confusing, but in a nutshell, malware is an umbrella term that includes:

Note: While adware is a type of malware, not every type of malware is adware, much like squares and rectangles respectively.

Spyware, specifically, collects the personal information of users and sells it to third parties. Sometimes, it installs Trojan viruses.3 PUPs, potentially unwanted programs, are also known as PUAs, or potentially unwanted applications. They often come bundled with legitimate free software. The most common types of PUAs are adware and spyware. 4

How Do You Get Adware?

Most people get adware by downloading a program, typically freeware or shareware, that contains it. Of course, people aren’t aware of this, as the program’s author signed up with the adware vendor to gain additional revenue (and probably isn’t advertising this fact). Otherwise, users can get adware by visiting devices that are infected with adware. If the user’s browser has vulnerabilities, the adware can download in what’s called a drive-by download.

Removing Android Adware - In Safe Mode
Removing Android Adware – In Safe Mode

By and large, adware is illegal in the U.S., but let’s dive a bit deeper into state and federal laws.

State Laws

Currently, 20 U.S. states plus Guam and Puerto Rico have laws about spyware, which includes adware.5 For example, California’s Consumer Protection Against Computer Spyware Act says, “A person or entity conducting business in this state, who is not an authorized user … shall not knowingly cause computer software to be copied onto the computer of a consumer.”6

Federal Laws

Federal law states that causing damage to 10 or more computers during a one-year period is a felony if the losses total $5,000 or more. That includes the installation of malicious spyware, which may include adware.7

Signs of Adware

There are various telltale signs that your device has an adware infection.

Pro Tip: None of these signs on their own necessarily indicate adware; for example, a VPN may slow down your device rather than adware. However, a combination of several of the below signs may indicate an adware infection.

Slow Computer and Browser

Adware scans bog down your processor and take up a lot of memory space, slowing down your computer significantly.

Many Ads

Sure, we’re all accustomed to running into dozens of online ads a day. But if you’re getting more pop-ups than usual or unclosable ads that keep redirecting you to other pages, this could be a sign of adware.


If too many ads show up, your program may crash and your device may freeze.

Changes to Browser’s Homepage

Is your browser’s homepage different without you having made any changes? You may be redirected to a new page that installs more PUPs in the form of adware or malware. You may also see:

  • Ads in places where they shouldn’t be
  • Common webpages not displaying properly
  • New extensions, plugins, software applications, and/or toolbars that you don’t remember installing

How to Prevent Adware

Adware can make your computer slow and your browsing experience a pain in the you-know-what. But don’t worry; there are multiple ways to prevent adware from infecting your devices.

  • Use antivirus software. The easiest way to block adware is to use antivirus software that can detect malware before it infects the rest of your device. The program will quarantine the adware in a virtual sandbox; we like to think of it as a timeout for adware.
  • Perform updates. Software updates may contain security patches, so update your device as soon as you can.
  • Only download apps from known app stores. The App Store and the Google Play Store scan all apps for malware, but if you jailbreak your device, then you could be downloading malicious apps. We like control as much as the next person, but when it comes to apps, it’s best to stick to Apple’s and Google’s recommendations.
  • Don’t click on pop-up ads. We all want flatter stomachs and whiter teeth, but resist clicking on pop-up ads, as they could contain even more PUPs/PUAs.
  • Beware of phishing. Phishing is sophisticated these days. Emails, links, and websites may appear legitimate, but it’s best to check their legitimacy before clicking; we recommend using a URL checker like Google’s Transparency Report.

How to Remove Adware

Despite the precautions, accidentally downloading adware is always a possibility whenever you’re online. Here’s how to remove adware if need be.

Safari (iOS and macOS)

Safari is the default browser on iOS and macOS devices. To remove adware from Safari, follow these steps:

  1. Update to the latest version of macOS.
  2. Once that update is complete, restart your device. Its built-in tool should remove the adware.
  3. Check your Applications folder for any unfamiliar apps. If there are, uninstall them.
  4. Check the Extensions tab in Safari to look for unfamiliar browser extensions. If you find any, turn them off.
  5. If you continue to see PUPs, PUAs, or adware, contact Apple online or by calling 1-800-275-2273.8

Chrome (Android)

Although Chrome is Google’s browser, you can use it on Android, Windows, macOS, or iOS devices. Follow these steps to remove problematic apps from Chrome on your Android:

  1. Press and hold the power button to turn the power off. Now, your device will start in safe mode.
  2. Remove recently deleted apps by going to the Google Play Store app.
  3. Click Menu.
  4. Click My Apps & Games.
  5. Select the recently deleted app and click Uninstall.
  6. Restart your Android.
  7. See if removing the apps got rid of the malware.
  8. Repeat as necessary.
Removing Android Adware - Choosing Apps to Uninstall
Removing Android Adware – Choosing Apps to Uninstall

To protect your Android from problematic apps:

  1. Go to the Google Play Store.
  2. Click Menu.
  3. Click Play Protect.
  4. Turn on Scan Device for Security Threats.
  5. Download an anti-malware app, like one from the best antivirus software for Androids.
  6. For more information, read about how to remove a virus on Android.
Removing Android Adware - Google Play Menu
Removing Android Adware – Google Play Menu

To stop notifications from certain websites:

  1. Go to Chrome.
  2. Click Web Page.
  3. Click More (the three vertical dots in the upper right-hand corner of the browser window).
  4. Click Site Settings.
  5. Click Permissions.
  6. Click Notifications.
  7. Set notifications to Off.
Resetting Settings on Chrome
Resetting Settings on Chrome

Chrome (Windows)

Follow these steps to remove adware from Chrome on your Windows device:

  1. Go to Chrome.
  2. Click More.
  3. Click Settings.
  4. Click Advanced.
  5. Click Reset and Clean Up.
  6. Click Clean Up Computer.
  7. Click Find.
  8. If you’re asked to remove unwanted software, click Remove.
  9. Reboot your computer.
  10. Click More.
  11. Click Settings.
  12. Click Advanced.
  13. Click Reset and Clean Up.
  14. Click Reset Settings.
Removing Adware on Windows
Removing Adware on Windows

Chrome (macOS, Chromebook, Linux)

Cleaning up Chrome adware on your macOS, Chromebook, or Linux device is easy.

  1. Open a Finder window.
  2. Click Applications.
  3. Look for unfamiliar programs.
  4. If you find any, right-click on them and drag them to your Trash folder.
  5. Empty your Trash folder.
  6. Go to Chrome.
  7. Click More.
  8. Click Settings.
  9. Click Advanced.
  10. Click Restore Settings to Their Original Defaults.
  11. Click Reset Settings.
Blocking Pop-Ups on the iPhone
Blocking Pop-Ups on the iPhone

Chrome (iOS)

iOS devices are like iPhones, and iPads don’t need antivirus software. However, if pop-ups are, well, popping up too much, here’s how to get rid of them:

  1. Go to Chrome.
  2. Click More.
  3. Click Settings.
  4. Click Content Settings.
  5. Click Block Pop-Ups.
  6. Turn on Block Pop-Ups.9

Internet Explorer (Windows)

Internet Explorer may not be the most popular browser anymore, and sure, Windows 10 comes with antivirus software already. But that doesn’t mean that adware can’t slip through. If it does, here’s how to remove it:

  1. Install the latest version of Microsoft.
  2. Remove threats with the Microsoft Safety Scanner.10
  3. If the Microsoft Safety Scanner didn’t detect the adware, submit a sample of it to the Microsoft Malware Protection Center.11

Mozilla Firefox (All Devices)

To remove adware from Firefox, you can either reset it to factory defaults or remove just the malicious toolbar. To reset it to factory defaults:

  1. Click on the hamburger menu button.
  2. Select the question mark icon at the bottom of the menu.
  3. Click Troubleshoot Information.
  4. Click Reset Firefox.

To remove the malicious toolbar:

  1. Click Menu.
  2. Click Add-Ons.
  3. Click Extensions.
  4. Select the toolbar you want to remove.
  5. Click Remove.
  6. Click Restart Now.12

Online Advertising

We’re huge fans of Mad Men, so adware is of particular interest to us. Of course, we’ve come a long way since ads were only in the paper and on billboards. Now, advertisements can be found almost anywhere online and offline, including our email inboxes and social media accounts. Let’s take a closer look at the ads themselves.

Types of Ads

On the internet, ads can be divided into three categories: PPC, PPI, and PPV. Alphabet soup, anyone?

  • PPC: PPC stands for “pay per click,” meaning that the advertiser only pays the publisher when a user clicks on their ad.
  • PPI: PPI stands for “pay per impression.” Instead of paying per click, advertisers pay a CPM, or a cost-per-thousand rate. In English? They pay every time 1,000 ads appear on users’ networks.13
  • PPV: Lastly, there’s “pay per view,” otherwise known as CPV, or cost per view. With PPV ads, advertisers pay every single time a user views their ad, as opposed to every time 1,000 ads appear on users’ networks.14

Why Companies Advertise

Looking at annoying pop-ups or tacky online banners, you may be wondering why companies advertise in the first place. Are ads really effective, and what is their purpose? Here’s why companies advertise, according to Duct Tape Marketing:

  • To increase revenue
  • To target customers
  • To create brand awareness
  • To add credibility
  • To amplify their mission15

History of Adware

Like Windows 95, Toy Story, and Van Halen, adware first appeared in 1995. At first, companies used it the same way they used print advertising, paying adware vendors to spread their material legitimately. However, people soon began adding adware into operating systems, breaking the law.16 Adware peaked from 2005 to 2008; after 2008, most legitimate companies learned to distance themselves from illegal adware, preferring legal forms of advertising.17

However, 2019 saw a shift where adware became more aggressive, with 24 million adware detections on Windows and 3 million adware detections on Macs. In fact, from 2019 to 2020, adware increased by 13 percent for consumers and by 463 percent for businesses.18 So, although legitimate companies have moved away from adware, as of 2020, adware was the largest type of malware threat for consumers and businesses, so it doesn’t seem to be going anywhere.


Adware can come in insidious forms, be it PUPs or phishing emails. However, removing adware from your devices is pretty simple, so even if they’re infected, it’s not the end of the world. After all, even the best antivirus software can’t catch everything! Learn more about how antivirus software works or how much antivirus software costs. You’ll be on your way to a clean and fast browsing experience in no time.

Adware FAQs

With a barrage of pop-ups and flashing online banners, adware can be overwhelming, but don’t worry — we’re here to answer the questions you ask the most.

  • What is an adware virus?

    Adware is actually not a virus but a type of malware that advertisers pay for. It displays ads on computers and mobile devices. Rather than being a virus, adware is a potentially unwanted program (PUP), otherwise known as a potentially unwanted application (PUA).

  • How dangerous is adware?

    Adware is not the most dangerous type of malware, but it can slow down your browser, crash your device, and sell your data to third parties to create targeted advertisements. Some adware can also hijack your browser, changing its settings without your knowledge or consent.

  • How do you stop adware?

    The easiest way to stop adware is to install antivirus software. You should also perform software updates as soon as possible, only download apps from your device’s official app stores, and avoid clicking on pop-up ads or suspicious links, emails, or websites.

  • Why is adware bad?

    Adware is bad because it can sell your data to third parties, slow down your device, change your settings, and potentially crash your browser. Adware also makes browsing the web a worse experience, as you’ll be barraged with redirects, banners, and pop-ups.

  1. Malwarebytes. (2021). Adware.

  2. Kaspersky. (2021). What is Adware: What You Should Know and How to Protect Yourself.

  3. UMass. (2021). Malware: Viruses, Spyware, Adware & Other Malicious Software.

  4. Norton. (2021). Malware.

  5. National Conference of State Legislatures. (2020). State Spyware Laws.

  6. California Legislative Information. (2021). BUSINESS AND PROFESSIONS CODE – BPC.

  7. (2015). Prosecuting Computer Crimes.

  8. Apple. (2021). About pop-up ads and windows in Safari.

  9. Google. (2021). Remove unwanted ads, pop-ups & malware.

  10. Microsoft. (2021). Microsoft Safety Scanner.

  11. Microsoft. (2021). Submit a file for malware analysis.

  12. Mozilla. (2018). Your browser is hijacked, now what?

  13. OnYourMarketing. (2021). The 3 Types of Paid Advertising: What They Are, How They Work, and When to Implement.

  14. (2012). What is PPV Advertising?

  15. Duct Tape Marketing. (2021). 5 Reasons Why You Must Advertise.

  16. Small Biz Daily. (2020). Adware Facts: 4 Critical Things You Didn’t Know About Malware.

  17. Investopedia. (2020). Adware.

  18. Malwarebytes. (2020). 2020 State of Malware Report.