How to Change Firefox Mouse Wheel Scroll Speed?

Perm url with updates: http://xahlee.org/mswin/Firefox_mouse_wheel_scroll_speed.html

How to Change Firefox Mouse Wheel Scroll Speed?

Xah Lee, 2011-05-30

  • ① In the url field, type about:config.
  • ② Scroll down to “mousewheel.withnokey.sysnumlines”. Double-click the line to set the value to “false”.
  • ③ Double-click the line “mousewheel.withnokey.numlines”, and set it to a number you like.

The change is immediate. You don't need to restart Firefox. This works in Linux too.

In a similar way, you can get mouse wheel to scroll one-page at a time. You can also adjust the mouse wheel tilt to do page up/down instead of horizontal scroll.

Set Mouse Wheel To Page Up/Down

  • ① Click on “mousewheel.withnokey.action” line.
  • ② Set the value to 1.

This will make the scroll wheel to go by pages.

Tech Detail

Here's tech detail, from the official doc at http://kb.mozillazine.org/About:config_entries.

mousewheel.* settings:

These fall into two groups: vertical and horizontal scrolling. The general form is:

  • mousewheel.‹modifier key›.‹type›
  • mousewheel.horizscroll.‹modifier key›.‹type›

The ‹modifier key› key is one of: “withaltkey”, “withcontrolkey”, “withmetakey”, “withnokey”, “withshiftkey”

Type is then one of: “action”, “numlines”, “sysnumlines”.


integer value that determines the type of action:

  • 0 - Scroll document by a number of lines (given by the numlines property)
  • 1 - Scroll document by one page
  • 2 - Move back/forward in history
  • 3 - Make text larger/smaller
  • 4 - Scroll document by a number of pixels (given by the numlines property)


number of lines to scroll by if action is set to value 0, or pixels if action is set to value 4; otherwise, this value is ignored.


use system preferences to determine how many lines to scroll by