diff --git a/src/Calculator/TextUnicodeConverter.php b/src/Calculator/TextUnicodeConverter.php
index 3b0cb4a..ef8d8ea 100644
--- a/src/Calculator/TextUnicodeConverter.php
+++ b/src/Calculator/TextUnicodeConverter.php
@@ -26,7 +26,7 @@ public static function convertTextToCodePoints(
         $values     = [];
         $lookingFor = 1;
 
-        for ($i = 0, $iMax = \strlen($string); $i < $iMax; $i++) {
+        for ($i = 0, $iMax = \strlen($string); $i < $iMax; ++$i) {
             $thisValue = \ord($string[$i]);
 
             if ($thisValue < 128) {