How to use custom filters | AdBlock Help Center

New to filters?

If you are new to ad-blocking or filter lists, we recommend starting with this article: Introduction to Filter Lists. Also, our blog post on how ad blockers work goes into greater detail if you're interested in what goes on behind the scenes.

Note: custom filters are only available on the AdBlock desktop extension. They are not available on mobile devices or the AdBlock for Safari Mac app.

Create custom filters

Our manual ad blocking feature allows you to customize web pages, and the resulting custom filters are added to your custom filters for you.
If you have a passing familiarity with coding, you can try writing your own custom filters. Adblock Plus created a really nice filter syntax tutorial and cheat-sheet: How to write filters and Adblock Plus filters explained.
Some pre-made custom filters can be found on the EasyList forums. This is where the list authors hang out, and where broken websites and unblocked ads are reported. You can search the EasyList forums for a website’s domain name and often find custom filters suggested by the list authors and other volunteers.
If you have questions about writing custom filters, the EasyList forums are the best place to get help. Many filter authors and filter rule aficionados may be willing to provide guidance.

Edit your custom filters

Chrome, Firefox, and Edge

Click the AdBlock icon on your browser’s toolbar, then the gear symbol on the dropdown menu.
On the options menu, select the Customize tab.
Click Edit to open the custom filters field.
Paste the filter exactly as given in the field (or delete any unwanted filters) and click Save.
Reload the webpage you are trying to change for the edit to take effect.

If adding a custom filter doesn't seem to work, you may need to clear your browser cache and cookies to clean up any old data that may be interfering.

Safari

Due to limitations imposed by Apple, custom filters are not available in the AdBlock for Safari Mac app.

Things to keep in mind

Custom filters enhance and override filter lists.

Filter lists block the vast majority of ads on web pages. What they can't block they can usually hide, with some exceptions. In some cases, the filters needed to block particularly stubborn ads also break some functionality on that site, and could even break completely unrelated websites. For this reason, the list authors are understandably reluctant to include such filters in their lists. Instead, they offer "custom" filters―filters you can use to enhance or override the filter lists. Custom filters affect only the people who choose to use them.

Custom filters can break websites.

List authors carefully test new filters before including them in their filter lists. It's impossible to test custom filters that thoroughly on every website. If your custom filters block too much, they can make websites unusable (but they can be removed).

Custom filters require maintenance.

Custom filters may stop working when a website’s design or layout changes or the website changes the way it serves ads to visitors. You will need to keep your custom filters up-to-date the way list authors do the filter lists.

Custom filters should be backed up.

If you have many custom filters, we recommend keeping a copy in a text file as a backup. Likewise, you can turn your custom filters into your own personal filter list: How to create your own personal filter list.