diff --git a/Parsedown.php b/Parsedown.php
index 757666e00..219158b80 100644
--- a/Parsedown.php
+++ b/Parsedown.php
@@ -141,7 +141,18 @@ protected function lines(array $lines)
 
                 foreach ($parts as $part)
                 {
-                    $shortage = 4 - mb_strlen($line, 'utf-8') % 4;
+                    if(function_exists('mb_strlen'))
+                    {
+                        $shortage = 4 - mb_strlen($line, 'UTF-8') % 4;
+                    }
+                    elseif(function_exists('iconv_strlen'))
+                    {
+                        $shortage = 4 - @iconv_strlen($line, 'UTF-8') % 4;
+                    }
+                    else
+                    {
+                        $shortage = 4 - preg_match_all("/.{1}/us",$line) % 4;
+                    }
 
                     $line .= str_repeat(' ', $shortage);
                     $line .= $part;