diff --git a/lcl/dialogs.pp b/lcl/dialogs.pp
index 2ffd66de9e..7132bd5961 100644
--- a/lcl/dialogs.pp
+++ b/lcl/dialogs.pp
@@ -342,6 +342,9 @@ type
     property ToPage: Integer read FToPage write FToPage default 0;
   end;
 
+const
+  MinimumDialogButtonWidth: integer = 90;
+  MinimumDialogButtonHeight: integer = 25;
 
 { MessageDlg }
 
diff --git a/lcl/include/promptdialog.inc b/lcl/include/promptdialog.inc
index 676d8b56a6..65e9404328 100644
--- a/lcl/include/promptdialog.inc
+++ b/lcl/include/promptdialog.inc
@@ -275,8 +275,8 @@ begin
     TextBox, DT_WORDBREAK or DT_INTERNAL or DT_CALCRECT);
 
   // calculate the width we need to display the buttons
-  MinBtnWidth:=75;
-  MinBtnHeight:=25;
+  MinBtnWidth:=Max(25,MinimumDialogButtonWidth);
+  MinBtnHeight:=Max(15,MinimumDialogButtonHeight);
   reqBtnWidth := 0;
 
   // create the buttons, without positioning
@@ -562,11 +562,9 @@ procedure TQuestionDlg.CalcButtonSize(AButton: TBitBtn; var w, h: Integer);
 var
   TxtSize: TSize;
 begin
-  w:=length(AButton.Caption)*10;
-  h:=25;
   TxtSize:=Canvas.TextExtent(AButton.Caption);
-  w:=TxtSize.cx;
-  h:=TxtSize.cy;
+  w:=Max(TxtSize.cx,MinimumDialogButtonWidth);
+  h:=Max(TxtSize.cy,MinimumDialogButtonHeight);
   if AButton.Kind<>bkCustom then begin
     inc(w,22); // icon
   end;