diff --git a/vhdlparser/TokenMgrError.cc b/vhdlparser/TokenMgrError.cc
index 6231196a877..2749940df4f 100644
--- a/vhdlparser/TokenMgrError.cc
+++ b/vhdlparser/TokenMgrError.cc
@@ -64,7 +64,7 @@ namespace parser {
 // i < 16 - guaranteed
 char hexChar(int i) {
   if (i < 10) {
-    return i - '0';
+    return i + '0';
   }
   return 'a' + (i - 10);
 }