diff --git a/dlls/user/controls.h b/dlls/user/controls.h
index a352d18a8ba..76271fb37d2 100644
--- a/dlls/user/controls.h
+++ b/dlls/user/controls.h
@@ -148,7 +148,6 @@ typedef struct
 #define DWLP_WINE_DIALOGINFO (DWLP_USER+sizeof(ULONG_PTR))
 
 extern DIALOGINFO *DIALOG_get_info( HWND hwnd, BOOL create );
-extern BOOL DIALOG_GetCharSize( HDC hdc, HFONT hFont, SIZE * pSize );
 extern void DIALOG_EnableOwner( HWND hOwner );
 extern BOOL DIALOG_DisableOwner( HWND hOwner );
 extern INT DIALOG_DoDialogBox( HWND hwnd, HWND owner );
diff --git a/dlls/user/dialog.c b/dlls/user/dialog.c
index a9ad30e4152..7bc90f2c4e2 100644
--- a/dlls/user/dialog.c
+++ b/dlls/user/dialog.c
@@ -143,38 +143,6 @@ BOOL DIALOG_DisableOwner( HWND hOwner )
         return FALSE;
 }
 
-/***********************************************************************
- *           DIALOG_GetCharSize
- *
- * Despite most of MSDN insisting that the horizontal base unit is
- * tmAveCharWidth it isn't.  Knowledge base article Q145994
- * "HOWTO: Calculate Dialog Units When Not Using the System Font",
- * says that we should take the average of the 52 English upper and lower
- * case characters.
- */
-BOOL DIALOG_GetCharSize( HDC hDC, HFONT hFont, SIZE * pSize )
-{
-    HFONT hFontPrev = 0;
-    const char *alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
-    SIZE sz;
-    TEXTMETRICA tm;
-
-    if(!hDC) return FALSE;
-
-    if(hFont) hFontPrev = SelectObject(hDC, hFont);
-    if(!GetTextMetricsA(hDC, &tm)) return FALSE;
-    if(!GetTextExtentPointA(hDC, alphabet, 52, &sz)) return FALSE;
-
-    pSize->cy = tm.tmHeight;
-    pSize->cx = (sz.cx / 26 + 1) / 2;
-
-    if (hFontPrev) SelectObject(hDC, hFontPrev);
-
-    TRACE("dlg base units: %ld x %ld\n", pSize->cx, pSize->cy);
-    return TRUE;
-}
-
-
 /***********************************************************************
  *           DIALOG_GetControl32
  *
@@ -532,11 +500,14 @@ static HWND DIALOG_CreateIndirect( HINSTANCE hInst, LPCVOID dlgTemplate,
         if (hUserFont)
         {
             SIZE charSize;
-            if (DIALOG_GetCharSize( dc, hUserFont, &charSize ))
+            HFONT hOldFont = SelectObject( dc, hUserFont );
+            charSize.cx = GdiGetCharDimensions( dc, NULL, &charSize.cy );
+            if (charSize.cx)
             {
                 xBaseUnit = charSize.cx;
                 yBaseUnit = charSize.cy;
             }
+            SelectObject( dc, hOldFont );
         }
         ReleaseDC(0, dc);
         TRACE("units = %d,%d\n", xBaseUnit, yBaseUnit );
@@ -1439,7 +1410,8 @@ DWORD WINAPI GetDialogBaseUnits(void)
 
         if ((hdc = GetDC(0)))
         {
-            if (DIALOG_GetCharSize( hdc, 0, &size )) units = MAKELONG( size.cx, size.cy );
+            size.cx = GdiGetCharDimensions( hdc, NULL, &size.cy );
+            if (size.cx) units = MAKELONG( size.cx, size.cy );
             ReleaseDC( 0, hdc );
         }
         TRACE("base units = %d,%d\n", LOWORD(units), HIWORD(units) );
diff --git a/dlls/user/dialog16.c b/dlls/user/dialog16.c
index d506c1bedb3..bdde9d2d63b 100644
--- a/dlls/user/dialog16.c
+++ b/dlls/user/dialog16.c
@@ -333,11 +333,14 @@ static HWND DIALOG_CreateIndirect16( HINSTANCE16 hInst, LPCVOID dlgTemplate,
         if (dlgInfo->hUserFont)
         {
             SIZE charSize;
-            if (DIALOG_GetCharSize( dc, dlgInfo->hUserFont, &charSize ))
+            HFONT hOldFont = SelectObject( dc, dlgInfo->hUserFont );
+            charSize.cx = GdiGetCharDimensions( dc, NULL, &charSize.cy );
+            if (charSize.cx)
             {
                 dlgInfo->xBaseUnit = charSize.cx;
                 dlgInfo->yBaseUnit = charSize.cy;
             }
+            SelectObject( dc, hOldFont );
         }
         ReleaseDC(0, dc);
         TRACE("units = %d,%d\n", dlgInfo->xBaseUnit, dlgInfo->yBaseUnit );
diff --git a/dlls/user/menu.c b/dlls/user/menu.c
index b1f29987f3a..913fbbbaffe 100644
--- a/dlls/user/menu.c
+++ b/dlls/user/menu.c
@@ -860,7 +860,9 @@ static void MENU_CalcItemSize( HDC hdc, MENUITEM *lpitem, HWND hwndOwner,
         MEASUREITEMSTRUCT mis;
         /* not done in Menu_Init: GetDialogBaseUnits() breaks there */
         if( !menucharsize.cx ) {
-            DIALOG_GetCharSize( hdc, hMenuFont, &menucharsize );
+            HFONT hOldFont = SelectObject( hdc, hMenuFont );
+            menucharsize.cx = GdiGetCharDimensions( hdc, NULL, &menucharsize.cy );
+            SelectObject( hdc, hOldFont );
             /* Win95/98/ME will use menucharsize.cy here. Testing is possible
              * but it is unlikely an application will depend on that */
             ODitemheight = HIWORD( GetDialogBaseUnits());