diff --git a/capinfos.c b/capinfos.c
index fee3c55af0..2581b32cc7 100644
--- a/capinfos.c
+++ b/capinfos.c
@@ -62,6 +62,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
+#include <locale.h>
 #include <errno.h>
 
 #ifdef HAVE_UNISTD_H
@@ -1297,6 +1298,9 @@ main(int argc, char *argv[])
     }
   }
 
+  /* Set the C-language locale to the native environment. */
+  setlocale(LC_ALL, "");
+
   if ((argc - optind) < 1) {
     usage(TRUE);
     exit(1);
@@ -1372,5 +1376,6 @@ main(int argc, char *argv[])
         exit(status);
     }
   }
+
   return overall_error_status;
 }
diff --git a/wsutil/str_util.c b/wsutil/str_util.c
index f2de5bfbee..5b5bc27450 100644
--- a/wsutil/str_util.c
+++ b/wsutil/str_util.c
@@ -107,15 +107,15 @@ gchar *format_size(gint64 size, format_size_flags_e flags) {
 	}
 
         if (size / power / power / power / power >= 10) {
-		g_string_printf(human_str, "%" G_GINT64_MODIFIER "d %s", size / power / power / power / power, prefix[pfx_off]);
+		g_string_printf(human_str, "%'" G_GINT64_MODIFIER "d %s", size / power / power / power / power, prefix[pfx_off]);
 	} else if (size / power / power / power >= 10) {
-		g_string_printf(human_str, "%" G_GINT64_MODIFIER "d %s", size / power / power / power, prefix[pfx_off+1]);
+		g_string_printf(human_str, "%'" G_GINT64_MODIFIER "d %s", size / power / power / power, prefix[pfx_off+1]);
 	} else if (size / power / power >= 10) {
-		g_string_printf(human_str, "%" G_GINT64_MODIFIER "d %s", size / power / power, prefix[pfx_off+2]);
+		g_string_printf(human_str, "%'" G_GINT64_MODIFIER "d %s", size / power / power, prefix[pfx_off+2]);
 	} else if (size / power >= 10) {
-		g_string_printf(human_str, "%" G_GINT64_MODIFIER "d %s", size / power, prefix[pfx_off+3]);
+		g_string_printf(human_str, "%'" G_GINT64_MODIFIER "d %s", size / power, prefix[pfx_off+3]);
         } else {
-		g_string_printf(human_str, "%" G_GINT64_MODIFIER "d ", size);
+		g_string_printf(human_str, "%'" G_GINT64_MODIFIER "d ", size);
 		is_small = TRUE;
 	}