diff --git a/runtime/src/main/cpp/KString.cpp b/runtime/src/main/cpp/KString.cpp
index f966081ee58..b5aa32fe1a0 100644
--- a/runtime/src/main/cpp/KString.cpp
+++ b/runtime/src/main/cpp/KString.cpp
@@ -740,7 +740,7 @@ OBJ_GETTER(Kotlin_String_toUtf8Array, KString thiz, KInt start, KInt size) {
   KStdString utf8;
   utf8::unchecked::utf16to8(utf16, utf16 + size, back_inserter(utf8));
   ArrayHeader* result = AllocArrayInstance(
-      theByteArrayTypeInfo, utf8.size() + 1, OBJ_RESULT)->array();
+      theByteArrayTypeInfo, utf8.size(), OBJ_RESULT)->array();
   ::memcpy(ByteArrayAddressOfElementAt(result, 0), utf8.c_str(), utf8.size());
   RETURN_OBJ(result->obj());
 }