Prevent Duplicate Tabs

Prevent Duplicate Tabs is a Chrome extension that blocks duplicate tabs automatically. If you open a link or URL that’s already open in another tab, it detects the duplicate and either closes it or switches you to the existing tab—so you get fewer tabs, less clutter, and lower memory use. No account, no sign-in; all settings and a local “duplicates prevented” count stay on your device.

Why use a duplicate tab blocker?

Opening the same page in multiple tabs wastes RAM, slows Chrome, and makes it harder to find the tab you need. A tab manager that prevents duplicate tabs keeps your browser lean: you avoid accidentally opening the same article, doc, or site twice, and you choose what happens when a duplicate is detected—close the new tab, close the old one, or switch to the right tab. Useful for researchers, developers, and anyone who keeps many tabs open.

How it works

When you open a new tab, the extension compares its URL to your open tabs (across all windows or only the current window—you choose). If it finds a match, it applies your chosen action right away. You can set a default behavior for all sites and override it per domain, so you can allow multiple Gmail tabs but block duplicates everywhere else.

Duplicate tab detection and actions