diff --git a/cocoa.m b/cocoa.m
index 8d36336..fe13952 100644
--- a/cocoa.m
+++ b/cocoa.m
@@ -40,7 +40,7 @@
 #define cgrect(nsrect) (*(CGRect *)&(nsrect))
 #define COCOA_MOUSE_EVENT \
         if (isTabletEnabled) { \
-            kbd_mouse_event((int)(p.x * 0x7FFF / screen.width), (int)((screen.height - p.y) * 0x7FFF / screen.height), 0, buttons); \
+            kbd_mouse_event((int)(p.x * 0x7FFF / (screen.width - 1)), (int)((screen.height - p.y) * 0x7FFF / (screen.height - 1)), 0, buttons); \
         } else if (isMouseGrabed) { \
             kbd_mouse_event((int)[event deltaX], (int)[event deltaY], 0, buttons); \
         } else { \
diff --git a/sdl.c b/sdl.c
index edd173e..1509397 100644
--- a/sdl.c
+++ b/sdl.c
@@ -312,8 +312,8 @@
 	}
 
 	SDL_GetMouseState(&dx, &dy);
-	dx = dx * 0x7FFF / width;
-	dy = dy * 0x7FFF / height;
+	dx = dx * 0x7FFF / (width - 1);
+	dy = dy * 0x7FFF / (height - 1);
     } else if (absolute_enabled) {
 	sdl_show_cursor();
 	absolute_enabled = 0;
diff --git a/vl.c b/vl.c
index baa9891..5b9e4ce 100644
--- a/vl.c
+++ b/vl.c
@@ -588,7 +588,7 @@
             if (qemu_put_mouse_event_current->qemu_put_mouse_event_absolute)
                 width = 0x7fff;
             else
-                width = graphic_width;
+                width = graphic_width - 1;
             mouse_event(mouse_event_opaque,
                                  width - dy, dx, dz, buttons_state);
         } else
diff --git a/vnc.c b/vnc.c
index 91c507e..2179d38 100644
--- a/vnc.c
+++ b/vnc.c
@@ -879,8 +879,8 @@
 	dz = 1;
 
     if (vs->absolute) {
-	kbd_mouse_event(x * 0x7FFF / vs->ds->width,
-			y * 0x7FFF / vs->ds->height,
+	kbd_mouse_event(x * 0x7FFF / (vs->ds->width - 1),
+			y * 0x7FFF / (vs->ds->height - 1),
 			dz, buttons);
     } else if (vs->has_pointer_type_change) {
 	x -= 0x7FFF;