diff --git a/src/string_utils.cpp b/src/string_utils.cpp
index ed73294c28931b8b568b69e65beae5090288d3b7..2f432214d8f5f16a15416ace89ab1af528a9202a 100644
--- a/src/string_utils.cpp
+++ b/src/string_utils.cpp
@@ -39,7 +39,7 @@ namespace jami {
 std::wstring
 to_wstring(const std::string& s)
 {
-    int slength = (int)s.length() + 1;
+    int slength = (int)s.length();
     int len = MultiByteToWideChar(CP_UTF8, 0, s.c_str(), slength, nullptr, 0);
     if (not len)
         throw std::runtime_error("Can't convert string to wchar");