diff --git a/src/Base64.php b/src/Base64.php
index e090613..e75aa4f 100644
--- a/src/Base64.php
+++ b/src/Base64.php
@@ -245,18 +245,12 @@ public static function decodeNoPadding(
             return '';
         }
         if (($srcLen & 3) === 0) {
-            if ($encodedString[$srcLen - 1] === '=') {
+            // If $strLen is not zero and it is divisible by 4, then its at least 4.
+            if ($encodedString[$srcLen - 1] === '=' || $encodedString[$srcLen - 2] === '=') {
                 throw new InvalidArgumentException(
                     "decodeNoPadding() doesn't tolerate padding"
                 );
             }
-            if (($srcLen & 3) > 1) {
-                if ($encodedString[$srcLen - 2] === '=') {
-                    throw new InvalidArgumentException(
-                        "decodeNoPadding() doesn't tolerate padding"
-                    );
-                }
-            }
         }
         return static::decode(
             $encodedString,