diff --git a/src/wp-includes/class-phpass.php b/src/wp-includes/class-phpass.php
index 5411b36483..055925b20f 100644
--- a/src/wp-includes/class-phpass.php
+++ b/src/wp-includes/class-phpass.php
@@ -173,8 +173,8 @@ class PasswordHash {
 		$itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
 
 		$output = '$2a$';
-		$output .= chr(ord('0') + $this->iteration_count_log2 / 10);
-		$output .= chr(ord('0') + $this->iteration_count_log2 % 10);
+		$output .= chr((int)(ord('0') + $this->iteration_count_log2 / 10));
+		$output .= chr((ord('0') + $this->iteration_count_log2 % 10));
 		$output .= '$';
 
 		$i = 0;
diff --git a/tests/phpunit/tests/passwordHash.php b/tests/phpunit/tests/passwordHash.php
new file mode 100644
index 0000000000..a764159e09
--- /dev/null
+++ b/tests/phpunit/tests/passwordHash.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Tests for the PasswordHash external library.
+ *
+ * @covers PasswordHash
+ */
+class Tests_PasswordHash extends WP_UnitTestCase {
+
+	public static function set_up_before_class() {
+		parent::set_up_before_class();
+
+		require_once ABSPATH . WPINC . '/class-phpass.php';
+	}
+
+	/**
+	 * Tests that PasswordHash::gensalt_blowfish() does not throw a deprecation
+	 * notice on PHP 8.1 for "Implicit conversion from float to int loses precision".
+	 *
+	 * Should this test fail, it will produce an error "E" in the results.
+	 *
+	 * @ticket 56340
+	 *
+	 * @covers PasswordHash::gensalt_blowfish
+	 *
+	 * @requires PHP 8.1
+	 */
+	public function test_gensalt_blowfish_should_not_throw_deprecation_notice_in_php81() {
+			$this->expectNotToPerformAssertions();
+
+			$hasher = new PasswordHash( 8, true );
+			$hasher->gensalt_blowfish( 'a password string' );
+	}
+
+}