diff --git a/src/Base32.php b/src/Base32.php
index 3ff41562d86ac4392c992517a14ebf73eb410be7..5054d736650588e332178ef342c0a43f73e72876 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 < $srcLen; ++$j) {
-                if ($encodedString[$srcLen - $j] === '=') {
+                if ($encodedString[$srcLen - $j - 1] === '=') {
                     throw new InvalidArgumentException(
                         "decodeNoPadding() doesn't tolerate padding"
                     );