diff --git a/api/include/opentelemetry/baggage/baggage.h b/api/include/opentelemetry/baggage/baggage.h
index 7f904f09a7..259fd7f3b6 100644
--- a/api/include/opentelemetry/baggage/baggage.h
+++ b/api/include/opentelemetry/baggage/baggage.h
@@ -249,7 +249,9 @@ class Baggage
     };
 
     auto from_hex = [](char c) -> char {
-      return std::isdigit(c) ? c - '0' : std::toupper(c) - 'A' + 10;
+      // c - '0' produces integer type which could trigger error/warning when casting to char,
+      // but the cast is safe here.
+      return static_cast<char>(std::isdigit(c) ? c - '0' : std::toupper(c) - 'A' + 10);
     };
 
     std::string ret;