diff --git a/src/Form/MenuTitleLengthSettingsForm.php b/src/Form/MenuTitleLengthSettingsForm.php
index 9b90c17..61eeac1 100644
--- a/src/Form/MenuTitleLengthSettingsForm.php
+++ b/src/Form/MenuTitleLengthSettingsForm.php
@@ -49,6 +49,19 @@ class MenuTitleLengthSettingsForm extends ConfigFormBase {
     return parent::buildForm($form, $form_state);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+     public function validateForm(array &$form, FormStateInterface $form_state) {
+    $menuTitleLength = $form_state->getValue('menu_title_length');
+
+     if (!is_numeric($menuTitleLength)) {
+       $form_state->setErrorByName('menu_title_length', $this->t('The menu title length must be an integer.'));
+     } elseif ($menuTitleLength < 0 || $menuTitleLength > 100) {
+       $form_state->setErrorByName('menu_title_length', $this->t('The menu title length must be an integer between 0 and 100.'));
+     }
+   }
+
   /**
    * {@inheritdoc}
    */