diff --git a/src/RunCmd.h b/src/RunCmd.h
index 46da053..529c125 100644
--- a/src/RunCmd.h
+++ b/src/RunCmd.h
@@ -44,7 +44,7 @@ class RunCmd : public Cmd
     "   consists of one or more (nitscf) scf steps, each consisting\n"
     "   of one or more (nite) electronic steps.\n"
     "   If the -atomic_density option is used, the initial charge\n"
-    "   density if a sum of atomic charge densities.\n\n";
+    "   density is a sum of atomic charge densities.\n\n";
   }
 
   int action(int argc, char **argv);