diff --git a/src/MDOutputHandler.php b/src/MDOutputHandler.php
index e6475c8..8d4d0a3 100644
--- a/src/MDOutputHandler.php
+++ b/src/MDOutputHandler.php
@@ -89,7 +89,7 @@ final class MDOutputHandler {
     private function _human_filesize(int $bytes, int $decimals = 2):string {
 
         $size = ['B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
-        $factor = floor((strlen((string)$bytes) - 1) / 3);
+        $factor = (int)floor((strlen((string)$bytes) - 1) / 3);
         return sprintf("%.{$decimals}f", $bytes / pow(1024, $factor)) . $size[$factor];
 
     }