Caps Lock (⇪ Caps Lock) is a button on acomputer keyboard that causes all letters ofbicameral scripts to be generated in capital letters. It is atoggle key: each press reverses the previous action. Some keyboards also implement a light to give visual feedback about whether it is on or off. Exactly what Caps Lock does depends on the keyboard hardware, theoperating system, thedevice driver, and thekeyboard layout. Usually, the effect is limited to letter keys. Letters of non-bicameral scripts (e.g.Arabic,Hebrew,Hindi) and non-letter characters are generated normally.
The Caps Lock key originated as ashift lock on mechanicaltypewriters. An early innovation in typewriters was the introduction of a second character on each typebar, thereby doubling the number of characters that could be typed, using the same number of keys. The second character was positioned above the first on the face of each typebar, and thetypewriter's shift key caused the entire type apparatus to move, physicallyshifting the positioning of the typebars relative to the ink ribbon. Just as in modern computer keyboards, the shifted position was used to produce capitals and secondary characters.
The shift lock was introduced so the shift operation could be maintained indefinitely without continuous effort. It mechanically locked the typebars in the shifted position, causing the upper character to be typed upon pressing any key. Because the two shift keys on a typewriter required more force to operate and were meant to be pressed by thelittle finger, it could be difficult to hold the shift down for more than two or three consecutive strokes, therefore the introduction of the shift lock was also meant to reduce finger muscle pain caused by repetitive typing.[citation needed]
Mechanical typewriter shift lock is typically set by pushing both shift and lock at the same time, and released by pressing shift by itself. Computer Caps Lock is set and released by the same key, and the Caps Lock behavior in mostQWERTY keyboard layouts differs from the shift-lock behavior in that it capitalizes letters but does not affect other keys, such as numbers or punctuation. Some early computer keyboards, such as theCommodore 64, had a shift lock but no Caps Lock; others, such as theBBC Micro, had both, only one of which could be enabled at a time.[citation needed]
There are some proposals to abolish the caps-lock key as being obsolete.[1][2][3] Pieter Hintjens, the CEO ofiMatix, started a "Capsoff" organization proposing hardware manufacturers delete the Caps Lock key.[1] Google has removed the Caps Lock on theChromebook keyboard, replacing it with the "Everything Button" (formerly the "Launcher" and "Search" buttons[4]); the caps-lock function is then reproduced using an "alt" key combination.[5][6]
In fact, the current German keyboard layout standardDIN 2137-01:2023-08 (like its preceding edition from 2018) specifies the function of the key as optional, to be replaced by other keys or key combinations. It recommends the function only to be invoked when it is pressed simultaneously with theControl key, while otherwise it acts as a “leftAltGr key”, thus enablingtouch typists to access all key combinations using AltGr without using two fingers of the same hand, which is considered to be anergonomic advantage. As a side effect, any inadvertent pressing of this key without pressing another key simultaneously has no effect.
Typical Caps Lock behavior is that pressing the key sets aninput mode in which all typed letters areuppercase, if applicable. The keyboard remains in Caps Lock mode and would generateall caps text until the key is pressed again. Keyboards often include a smallLED to indicate that Caps Lock is active, either on the key itself or in a dedicated indicators area, whereScroll Lock andNum Lock indicators are also located. On the originalIBM PC keyboard, this LED was exclusively controlled by the keyboard. Since the introduction ofIBM PC/AT, it is under control of the operating system. Small keyboards, such asnetbook keyboards, forgo the indicators to conserve space, instead providing software that gives on-screen or audio feedback.
In most cases, the status of the Caps Lock key only changes the meaning of the alphabet keys, not that of any other key.Microsoft Windows enforces this behavior only when a keyboard layout for a Latin-based script is active, e.g. the "English (United States)" layout but not the "Persian" layout. On certain non-QWERTY keyboard layouts, such as theFrench AZERTY and theGerman QWERTZ, Caps Lock still behaves like a traditional Shift lock, i.e., the keyboard behaves as if theShift key is held down, causing the keyboard to input the alternative values of the keys; example the5 key generates "%" when⇪ Caps Lock is pressed. This is not true for the layout "German (IBM)".
Depending on the keyboard layout used, theShift key, when pressed in combination with a Latin-based letter button while Caps Lock is already on, is either ignored, or reverses the effect of Caps Lock, so that typed characters are inlowercase again. Microsoft Windows enforces the latter. RISC OS offers both – Caps Lock alone chooses the former, Shift-Caps Lock the latter.
While the typical locking behavior on keyboards with a⇪ Caps Lock key is that of a toggle, each press reversing the shift state, some keyboard layouts implement a combi mode,[example needed] where pressing a Shift key in Caps Lock mode will also release the Caps Lock mode, just as it typically happens in Shift lock mode.
Some keyboard drivers[example needed] include a configuration option to deactivate the Caps Lock key. This behavior allows users to decide themselves whether they want to use the key, or to disable it to prevent accidental activation.
In theUnix communities of theex-USSR countries, Caps Lock key is traditionally used as input language switcher, convenient for usage withtouch typing. Support for this is present inKDE,[7]GNOME and other desktop environments. DefaultRussian andUkrainian layouts forFreeBSD specify Caps Lock as input language switcher. In Microsoft Windows, third-party utilities are needed to enable this behavior.[8][9] In such configurations, the original Caps Lock function is reached with the⇧ Shift+⇪ Caps Lock combination.
Most apps that request users to input apassword do not display it on screen, so as not to expose it to prying eyes. A user who does not pay proper attention to the Caps Lock indicator might type the wrong password (in which all small letters become capital letters or vice versa). As such, help guides, tech support materials, and app user interfaces may include warnings on checking the Caps Lock state before typing a password. In Microsoft Windows login screens, a warning that Caps Lock is on is shown in a balloon near the field. InmacOS, when Caps Lock is on, a Caps Lock symbol (U+21EA ⇪UPWARDS WHITE ARROW FROM BAR) is displayed inside a password field.
Some Windows keyboard layouts, such as Swiss German, have anSGCAPS flag on some keys, where those keys generate unrelated, non-uppercase symbols when pressed before⇧ Shift,[10] creating a 5th level (and a 6th level when⇪ Caps Lock is on and⇧ Shift is held) for typing symbols on a single key.
Below is an example of theü key with theSGCAPS feature in the Swiss German layout.
SGCAPS is named after the first keyboard layout to use this feature. (SwissGermanCAPS Lock).[11]
Since its inception, theIBM PC keyboard had a Caps Lock. In the first version for PC/XT, Caps Lock was located to the bottom right of the letter keys area. Subsequent models switched the places of the Caps Lock key and theControl key. As such, Caps Lock has since been placed on left edge of the keyboard, above theShift key and below theTab key, next to letter A. This layout has become thede facto popular standard.
The keyboards of some earlycomputer terminals, including theTeletype Model 33 ASR andLear-SieglerADM-3A, theApple II, and a fewApple Keyboard models retained the Control key where PC/XT first had it; Caps Lock was either absent on these devices or was placed elsewhere. This layout was preserved for laterworkstation systems and is often associated withUnix workstations. Keyboards fromSun Microsystems came in two layouts; "Unix" and "PC-style", with the Unix layout having the traditional placing of the Control key and other keys.[12] TheAmiga computers all had both the Control key and Caps Lock key in this spot at half the width.
Some users of keyboards with Caps Lock on the left remap the keys to exchange Control and Caps Lock, finding the traditional location moreergonomic for using programs benefiting from use of the Control key. Keyboard layout preferences specifically to address this need are available in some operating systems. Some keyboards even provide a switch on the bottom to logically swap the two keys in hardware.[13][14]
TheHappy Hacking Keyboard and the keyboards produced forOLPC XO computers also have the Control key in this location, while not including a Caps Lock.[15] Beginning with theGoogleCr-48,Chromebooks have omitted Caps Lock in favor of either a Search button or an "Everything Button".[16] Holding downAlt and pressing the Everything Button enables Caps Lock, which is enabled until Shift is pressed.[6]
June 28 and October 22 are semiannually observed as International Caps Lock Day as a parody holiday created in October 2000 by Derek Arnold, a user onMetaFilter. The second observation on June 28 was added by Arnold in memory of American pitchmanBilly Mays.[17][18][19]
| Esc | F1 | F2 | F3 | F4 | F5 | F6 | F7 | F8 | F9 | F10 | F11 | F12 | PrtScn/ SysRq | Scroll Lock | Pause/ Break | |||||||||
 | Insert | Home | PgUp | Num Lock | ∕ | ∗ | − | |||||||||||||||||
| Delete | End | PgDn | 7 | 8 | 9 | + | ||||||||||||||||||
| 4 | 5 | 6 | ||||||||||||||||||||||
| ↑ | 1 | 2 | 3 | Enter | ||||||||||||||||||||
| ← | ↓ | → | 0 Ins | . Del | ||||||||||||||||||||