Checks if the specified window exists and returns the unique ID (HWND) of the first matching window.

UniqueID := WinExist(WinTitle, WinText, ExcludeTitle, ExcludeText)


A window title or other criteria identifying the target window. See WinTitle.
If present, this parameter must be a substring from a single text element of the target window (as revealed by the included Window Spy utility). Hidden text elements are detected if DetectHiddenText is ON.
Windows whose titles include this value will not be considered.
Windows whose text include this value will not be considered.

Return Value

This function returns the unique ID (HWND) (as hexadecimal integer) of the first matching window (0 if none).

Since all non-zero numbers are seen as "true", the statement if WinExist(WinTitle) is true whenever WinTitle exists.


If all parameters are omitted, the Last Found Window will be checked to see if it still exists.

If a qualified window exists, the Last Found Window will be updated to be that window.

To discover the HWND of a control (for use with Post/SendMessage or DllCall), use ControlGet Hwnd or MouseGetPos.

SetWinDelay does not apply to this function.

Window titles and text are case sensitive. Hidden windows are not detected unless DetectHiddenWindows has been turned on.

IfWinExist / IfWinNotExist, WinActive(), SetTitleMatchMode, DetectHiddenWindows, Last Found Window, Process, WinActivate, WinWaitActive, WinWait, WinWaitClose, #IfWinActive/Exist


Activates either Notepad or another window, depending on which of them was found by the WinExist functions above. Note that the space between an "ahk_" keyword and its criterion value can be omitted; this is especially useful when using variables, as shown by the second WinExist.

if WinExist("ahk_class Notepad") or WinExist("ahk_class" ClassName)
    WinActivate ; Use the window found by WinExist.

Retrieves and reports the unique ID (HWND) of the active window.

MsgBox % "The active window's ID is " WinExist("A")

Returns if the calculator does not exist.

if not WinExist("Calculator")