diff --git a/dlls/msi/database.c b/dlls/msi/database.c
index 425486e5654..bad40b8011a 100644
--- a/dlls/msi/database.c
+++ b/dlls/msi/database.c
@@ -348,7 +348,7 @@ static LPWSTR msi_build_createsql_prelude(LPWSTR table)
 
     static const WCHAR create_fmt[] = {'C','R','E','A','T','E',' ','T','A','B','L','E',' ','`','%','s','`',' ','(',' ',0};
 
-    size = sizeof(create_fmt) + lstrlenW(table) - 2;
+    size = sizeof(create_fmt)/sizeof(create_fmt[0]) + lstrlenW(table) - 2;
     prelude = msi_alloc(size * sizeof(WCHAR));
     if (!prelude)
         return NULL;