“Your own greatest enemy is yourself,” goes the famous adage. This may be true, but for us high-schoolers, our own greatest enemies are ourselves…and procrastination. There has been many a night–or morning, as it were–in which we have stayed up long past twelve, feverishly cramming for a history exam or pulling together that forgotten collateral. We’ve all been told to simply “stay off Facebook” or “log out of Tumblr,” but these tactics don’t work, because it is all too easy to open a new tab and log back in.

But never fear! With these simple (and free!) web extensions, not only will you be able to resist the urge to scroll through your dashboard or check your notifications, you won’t be able to access these sites at all, practically guaranteeing that you’ll get your homework done before midnight.

1. StayFocusd

Google Chrome only (sorry, Firefox users!)

Allows a self-allotted time for websites placed on a “blocked” list.

After the time is setup, you will not be allowed access to these sites until the end of the day.

2. DropCloth

Blacks out everything on your desktop, except for currently active window.

3. Isolator

The Mac version of DropCloth.

4. Swept Away

Windows only

After a user-set amount of time, it automatically minimizes inactive windows in the background.

5. Obtract

Mac only

Every hour, users are allowed five minutes on a non-productive site.

After the five minutes are up, the user needs to solve mazes of increasing difficulty to access these sites.

So the next time you stay up until the wee hours of morning, consider putting these extensions to good use. With their help, you’ll be able to combat that great enemy of all high-schoolers, and walk out of battle victorious.