diff --git a/src/terminal-encoding.c b/src/terminal-encoding.c
index d0ebac2..ae7bab9 100644
--- a/src/terminal-encoding.c
+++ b/src/terminal-encoding.c
@@ -248,7 +248,7 @@ terminal_encoding_is_valid (TerminalEncoding *encoding)
 			                       " input  \"%s\"\n",
 			                       ascii_sample);
 			_terminal_debug_print (TERMINAL_DEBUG_ENCODINGS,
-			                       " output \"%s\" bytes read %u written %u\n",
+			                       " output \"%s\" bytes read %" G_GSIZE_FORMAT " written %" G_GSIZE_FORMAT "\n",
 			                       converted ? converted : "(null)", bytes_read, bytes_written);
 			if (error)
 				_terminal_debug_print (TERMINAL_DEBUG_ENCODINGS,