diff --git a/dlls/msi/dialog.c b/dlls/msi/dialog.c
index 85d58592e7f..c0ff2043a5e 100644
--- a/dlls/msi/dialog.c
+++ b/dlls/msi/dialog.c
@@ -309,7 +309,7 @@ static UINT msi_dialog_add_font( MSIRECORD *rec, LPVOID param )
 
     /* create a font and add it to the list */
     name = MSI_RecordGetString( rec, 1 );
-    font = msi_alloc( sizeof *font + strlenW( name )*sizeof (WCHAR) );
+    font = msi_alloc( FIELD_OFFSET( msi_font, name[strlenW( name ) + 1] ));
     strcpyW( font->name, name );
     list_add_head( &dialog->fonts, &font->entry );
 
@@ -414,7 +414,7 @@ static msi_control *msi_dialog_create_window( msi_dialog *dialog,
 
     style |= WS_CHILD;
 
-    control = msi_alloc( sizeof *control + strlenW(name)*sizeof(WCHAR) );
+    control = msi_alloc( FIELD_OFFSET( msi_control, name[strlenW( name ) + 1] ));
     if (!control)
         return NULL;
 
diff --git a/dlls/msi/table.c b/dlls/msi/table.c
index c5aa6851036..e2186fcb3cf 100644
--- a/dlls/msi/table.c
+++ b/dlls/msi/table.c
@@ -2141,7 +2141,7 @@ UINT TABLE_CreateView( MSIDATABASE *db, LPCWSTR name, MSIVIEW **view )
     else if ( !strcmpW( name, szStorages ) )
         return STORAGES_CreateView( db, view );
 
-    sz = sizeof *tv + lstrlenW(name)*sizeof name[0] ;
+    sz = FIELD_OFFSET( MSITABLEVIEW, name[lstrlenW( name ) + 1] );
     tv = msi_alloc_zero( sz );
     if( !tv )
         return ERROR_FUNCTION_FAILED;