> For the complete documentation index, see [llms.txt](https://www.adblocklabs.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.adblocklabs.com/docs/getting-started/about-adblock.md).

# About AdBlock

AdBlock is a system-wide ad blocker and privacy tool for Windows. An ad blocker removes advertisements from the websites you browse, stopping ad and tracking scripts before they load, so unwanted content never reaches your screen.

Unlike a browser extension, AdBlock works at the system level: one install protects every browser on your PC, not just the one you added an extension to. For the full comparison, see [System-level vs. browser ad blockers](/docs/core-concepts/system-level-vs.-browser-ad-blockers-whats-the-difference.md).

## What AdBlock blocks

* **Pop-ups and pop-unders**
* **Banner ads**
* **Video ads**, including [YouTube ads](https://www.adblocklabs.com/news/can-you-block-ads-on-youtube-here-is-how)
* **Autoplay ads with sound**
* **Tracking and behavioral ads**
* **Malvertising** — ads that carry malware

## How it works

AdBlock detects and stops ad-related traffic before it loads:

* **Ad filtering** — recognizes known ad and tracker sources and blocks requests to them.
* **Tracker blocking** — stops third-party scripts from collecting your data.
* **Faster pages** — with ads gone, pages load quicker and use less bandwidth and CPU.
* **Safer browsing** — blocks malicious ads that spread malware or phishing.

Because it works across your whole system, the same protection applies in every browser, and it keeps working when you switch between them. To see how AdBlock filters encrypted traffic safely, see [What is HTTPS filtering](/docs/core-concepts/what-is-https-filtering.md).

## Is using an ad blocker legal?

Yes. Using an ad blocker is legal in most countries, including the United States. Ad blockers put you in control of your own browsing experience and protect your privacy. Many sites now offer lighter, ad-free, or alternatively funded experiences for people who prefer to browse without ads.

> **Ready for a cleaner, faster, safer internet?** [Start a free trial](https://www.adblocklabs.com/) — no credit card required, and every paid plan comes with a 30-day money-back guarantee.

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h4><i class="fa-rocket-launch" style="color:$primary;">:rocket-launch:</i></h4></td><td><strong>Installing AdBlock</strong></td><td>Learn about the AdBlock install process and OS compatibility.</td><td><a href="/pages/c3101d8e098a6f696c75f6bda47d0ea5fdade1e5">/pages/c3101d8e098a6f696c75f6bda47d0ea5fdade1e5</a></td></tr><tr><td><h4><i class="fa-compass" style="color:$primary;">:compass:</i></h4></td><td><strong>How to activate your AdBlock license</strong></td><td>Learn how to activate your AdBlock license and start using your AdBlock subscription.</td><td><a href="/pages/jiNaym2DBJ2OMCKM7nFp">/pages/jiNaym2DBJ2OMCKM7nFp</a></td></tr></tbody></table>