LeechBlock NG is a simple productivity tool: an extension for the Firefox web browser designed to block those time-wasting sites that can suck the life out of your working day. (You know: the ones that rhyme with ‘Blue Cube’, ‘Space Hook’, ‘Sticky Media’, ‘Quitter’, and the like.) All you need to do is specify which sites to block and when to block them.
You can specify up to six sets of sites to block, with different times and days for each set. You can block sites within fixed time periods (e.g., between 9am and 5pm), after a time limit (e.g., 10 minutes in every hour), or with a combination of time periods and time limit (e.g., 10 minutes in every hour between 9am and 5pm).
The sites to block can be specified using wildcards (e.g.,
*.somesite.com) and exceptions (e.g.,
With the lockdown feature, you can block sites immediately for a specified duration.
You can also set a password or random access code for LeechBlock’s options page, just to slow you down in moments of weakness!
Important note #1: The legacy version of LeechBlock is not compatible with Firefox 57 and above. If you’re using the old version, you should uninstall it and install the new version. Further information is available here.
Important note #2: LeechBlock is not designed for parental control or for blocking offensive content. You are advised not to try to use it for these purposes.
Important note #3: Although LeechBlock prevents you from browsing sites (at the specified times) it may still allow your Firefox browser to briefly connect to those sites (so that, e.g., your IP address may still be logged by the blocked site). If you want to prevent any such connection, you should use some lower-level blocking method (e.g., install and configure a HOSTS file manager like HostsMan).