diff --git a/include/json_html_serializer.hpp b/include/json_html_serializer.hpp
index be9efc4..3efc224 100644
--- a/include/json_html_serializer.hpp
+++ b/include/json_html_serializer.hpp
@@ -327,9 +327,9 @@
 
     const bool isNegative = std::is_same<NumberType, int64_t>::value &&
                             !(number >= 0); // see issue #755
-    uint64_t absValue;
+    uint64_t absValue = 0;
 
-    unsigned int nChars;
+    unsigned int nChars = 0;
 
     if (isNegative)
     {