Scroll wheel
A wheel on a mouse for scrolling electronic displays.
A scroll wheel is a component used to scroll through content on an electronic screen. Most commonly, it refers to the wheel on a computer mouse, often called a mouse wheel. Typically made of hard plastic with a rubbery coating, it is built around an internal rotary encoder. It sits between the left and right mouse buttons, perpendicular to the mouse's surface. In many cases, the wheel can also be pressed down to act as an extra button.
The wheel is positioned horizontally between the buttons and is primarily used for vertical scrolling. Rolling the wheel from bottom to top is called scrolling "upward" or "forward," while rolling from top to bottom is "downward" or "backward." In a graphical user interface, an upward motion moves the window's content downward (and the scrollbar thumb upward), and vice versa. Some setups, known as "natural scrolling," reverse this effect.
On most mice, pressing down on the scroll wheel activates it as a third, middle mouse button, often called the scroll button. Some mice allow horizontal scrolling by tilting the wheel left or right, or they include an additional wheel on a perpendicular axis elsewhere on the mouse. The wheel is often designed with detents that turn in discrete steps rather than smoothly, helping users gauge how far they are scrolling.
Scroll wheels are common on modern computer mice and have become a standard part of the hardware interface, though non-wheeled mice are still available. Some user interfaces, such as Cinnamon, let users adjust brightness or volume by pointing at a taskbar icon and rolling the wheel. Spinners and drop-down lists in many toolkits also allow value changes using the mouse wheel.
The scroll wheel on a mouse has been invented multiple times by different people unaware of each other's work. Other scrolling controls on a mouse, and the use of a wheel for scrolling, both predate the combination of wheel and mouse. The earliest known example of a scrolling control is a 1985 prototype from NTT, Japan and ETH Zürich, Switzerland, which had a thumb-operated analog button/toggle switch on the side for smooth scrolling. At the 1989 ACM SIGCHI conference, Gina Danielle Venolia from Apple presented a mouse prototype with a horizontal thumb-wheel for scrolling or navigating inwards and outwards (zooming or moving along the third axis in 3D space).
- First commercial mouse with scroll wheel
- Genius EasyScroll (also available as Mouse Systems ProAgio), released in 1995 by KYE Systems
- Popularized by
- Microsoft IntelliMouse in 1996, with support in Microsoft Office 97
- Earliest known prototype with scrolling
- Mighty Mouse prototype (1985) by NTT, Japan and ETH Zürich, Switzerland (Kunio Ōno, Ken'ichi Fukaya and Jürg Nievergelt)
- Early apple prototype
- Presented by Gina Danielle Venolia at ACM SIGCHI in 1989, with a horizontal thumb-wheel
Lore & Background
The scroll wheel on a mouse has been invented multiple times by different people unaware of the others' work. The earliest known example of a scrolling control on a mouse is the Mighty Mouse prototype developed jointly by NTT, Japan and ETH Zürich, Switzerland in 1985 by Kunio Ōno, Ken'ichi Fukaya and Jürg Nievergelt; it had a thumb-operated combined analog button/toggle switch on the side for smooth scrolling. At the ACM SIGCHI conference in 1989, Gina Danielle Venolia from Apple presented a mouse prototype with a horizontal thumb-wheel for scrolling, or for navigating inwards and outwards: zooming or along the third axis in 3D space. In her patent application from 1992 there are two vertical wheels: left and right of the button(s).
The first commercial mouse with a scroll wheel was released in 1995 by the Taiwanese company KYE Systems, named Genius EasyScroll and also available as Mouse Systems ProAgio. The scroll wheel was popularized by the Microsoft IntelliMouse in 1996 along with support for the mouse wheel in Microsoft Office 97, based on ideas developed by Eric Michelman since 1993 with input from Chris Graham. Scroll wheels can also be found on PDAs and mobile phones such as early Sony models, BlackBerry devices and Nokia 7110, which usually have the function of navigating through menus. They have also appeared on keyboards, particularly on Logitech and Microsoft models, usually located to the left of the caps lock key.
Reader's Guide
The scroll wheel has become an integral part of the hardware interface on modern computer mice, though non-wheeled mice are still available. Its functionality extends beyond simple scrolling: in graphical user interfaces, rolling the wheel upward moves window contents downward and the scrollbar thumb upward, while downward rolling does the reverse; some configurations (called 'natural scrolling') invert this effect. On most mice, pressing the wheel acts as a third, middle mouse button. Some mice's scroll wheels can scroll horizontally by tilting left or right, or have an additional wheel on a perpendicular axis. The wheel is often engineered with detents to turn in discrete steps, helping the operator intuit scrolling distance. Scroll-wheel motion is also used to control other aspects of a system, such as switching between options, zooming in or out, or incrementing or decrementing values. In first-person shooter games, scroll wheels are often used to switch between weapons or to lean left and right if horizontal scrolling is available, or to zoom a telescopic sight. CAD applications like Autodesk's AutoCAD use the mouse wheel to navigate the drawing space, a de facto standard in many 3D applications; Trimble's SketchUp uses the scroll wheel to zoom in and out, while a wheel-click and drag performs orbit. Alternatives to the scroll wheel include scroll balls, pointing sticks, integrated touchpads, optical sensors, and on some laptops, touchpad gestures or pointing-stick scrolling with a dedicated button.
Did You Know?
- The first commercial mouse with a scroll wheel was the Genius EasyScroll, released in 1995 by KYE Systems.
- Scroll wheels have also appeared on keyboards, usually located to the left of the caps lock key.
Frequently Asked Questions
Who is credited with inventing the scroll wheel?
The earliest known scrolling prototype is the Mighty Mouse, developed in 1985 by researchers at NTT in Japan and ETH Zürich in Switzerland, including Kunio Ōno, Ken'ichi Fukaya, and Jürg Nievergelt. An Apple prototype featuring a horizontal thumb-wheel was also presented by Gina Danielle Venolia at ACM SIGCHI in 1989, though it never reached consumers.
What was the first commercially available mouse with a scroll wheel?
The Genius EasyScroll, sold by KYE Systems in 1995, holds that distinction (it was also marketed under the Mouse Systems ProAgio name). It beat Microsoft's popularization of the feature by a full year.
How does a scroll wheel work mechanically?
Beneath the hard plastic shell and rubbery grip coating, the wheel is built around an internal rotary encoder that converts rotational movement into digital scroll signals. It is positioned horizontally between the left and right mouse buttons, perpendicular to the mouse's top surface.
What product made the scroll wheel a mainstream standard?
Microsoft's IntelliMouse, released in 1996, brought the wheel to a massive audience, and its integration into Microsoft Office 97 made scrolling a default expectation for office workers. Before that pairing, the feature was largely unknown to the general public.
Can the scroll wheel be used for anything besides vertical scrolling?
On many mice, pressing the wheel down acts as a third, middle button used for actions like opening links in a new browser tab. Some models also allow the wheel to tilt sideways, enabling horizontal scrolling through wide documents or spreadsheets.
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