diff --git a/src/Base32.php b/src/Base32.php
index 2c3ee61dc700f459da63d3e99e8ec4da84ce4aa1..b4857c121fd73ddcde6281a1181289eac9e3428a 100644
--- a/src/Base32.php
+++ b/src/Base32.php
@@ -197,7 +197,7 @@ abstract class Base32 implements EncoderInterface
         }
         if (($srcLen & 7) === 0) {
             for ($j = 0; $j < 7; ++$j) {
-                if ($encodedString[$srcLen - 1] === '=') {
+                if ($encodedString[$srcLen - $j] === '=') {
                     throw new InvalidArgumentException(
                         "decodeNoPadding() doesn't tolerate padding"
                     );