diff --git a/core/lib/Drupal/Core/Config/Entity/Query/Condition.php b/core/lib/Drupal/Core/Config/Entity/Query/Condition.php
index bb20fbe..e6d2d52 100644
--- a/core/lib/Drupal/Core/Config/Entity/Query/Condition.php
+++ b/core/lib/Drupal/Core/Config/Entity/Query/Condition.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Config\Entity\Query;
 
+use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Entity\Query\ConditionBase;
 use Drupal\Core\Entity\Query\ConditionInterface;
 use Drupal\Core\Entity\Query\QueryException;
@@ -33,6 +34,15 @@ public function compile($configs) {
         if (!isset($condition['operator'])) {
           $condition['operator'] = is_array($condition['value']) ? 'IN' : '=';
         }
+
+        // Lowercase condition value(s) for case-insensitive matches.
+        if (is_array($condition['value'])) {
+          $condition['value'] = array_map('Drupal\Component\Utility\Unicode::strtolower', $condition['value']);
+        }
+        elseif (!is_bool($condition['value'])) {
+          $condition['value'] = Unicode::strtolower($condition['value']);
+        }
+
         $single_conditions[] = $condition;
       }
     }
@@ -150,6 +160,11 @@ protected function matchArray(array $condition, array $data, array $needs_matchi
    */
   protected function match(array $condition, $value) {
     if (isset($value)) {
+      // We always want a case-insensitive match.
+      if (!is_bool($value)) {
+        $value = Unicode::strtolower($value);
+      }
+
       switch ($condition['operator']) {
         case '=':
           return $value == $condition['value'];
diff --git a/core/lib/Drupal/Core/Entity/Query/QueryInterface.php b/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
index d7110ca..5c32717 100644
--- a/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
+++ b/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
@@ -46,9 +46,9 @@ public function getEntityType();
    * @endcode
    *
    * @param $value
-   *   The value for $field. In most cases, this is a scalar. For more complex
-   *   options, it is an array. The meaning of each element in the array is
-   *   dependent on $operator.
+   *   The value for $field. In most cases, this is a scalar and it's treated as
+   *   case-insensitive. For more complex options, it is an array. The meaning
+   *   of each element in the array is dependent on $operator.
    * @param $operator
    *   Possible values:
    *   - '=', '<>', '>', '>=', '<', '<=', 'STARTS_WITH', 'CONTAINS',
diff --git a/core/modules/system/lib/Drupal/system/Form/DateFormatFormBase.php b/core/modules/system/lib/Drupal/system/Form/DateFormatFormBase.php
index 2205942..ccfc043 100644
--- a/core/modules/system/lib/Drupal/system/Form/DateFormatFormBase.php
+++ b/core/modules/system/lib/Drupal/system/Form/DateFormatFormBase.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Ajax\AjaxResponse;
 use Drupal\Core\Ajax\ReplaceCommand;
+use Drupal\Core\Config\Entity\ConfigStorageController;
 use Drupal\Core\Datetime\Date;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Drupal\Core\Datetime\DrupalDateTime;
@@ -42,19 +43,29 @@
   protected $dateService;
 
   /**
+   * The date format storage controller.
+   *
+   * @var \Drupal\Core\Config\Entity\ConfigStorageController
+   */
+  protected $dateFormatStorage;
+
+  /**
    * Constructs a new date format form.
    *
    * @param \Drupal\Core\Entity\Query\QueryFactory $query_factory
    *   The entity query factory.
    * @param \Drupal\Core\Datetime\Date $date_service
    *   The date service.
+   * @param \Drupal\Core\Config\Entity\ConfigStorageController $date_format_storage
+   *   The date format storage controller.
    */
-  public function __construct(QueryFactory $query_factory, Date $date_service) {
+  public function __construct(QueryFactory $query_factory, Date $date_service, ConfigStorageController $date_format_storage) {
     $date = new DrupalDateTime();
     $this->patternType = $date->canUseIntl() ? DrupalDateTime::INTL : DrupalDateTime::PHP;
 
     $this->queryFactory = $query_factory;
     $this->dateService = $date_service;
+    $this->dateFormatStorage = $date_format_storage;
   }
 
   /**
@@ -63,7 +74,8 @@ public function __construct(QueryFactory $query_factory, Date $date_service) {
   public static function create(ContainerInterface $container) {
     return new static(
       $container->get('entity.query'),
-      $container->get('date')
+      $container->get('date'),
+      $container->get('entity.manager')->getStorageController('date_format')
     );
   }
 
@@ -183,16 +195,12 @@ public function validate(array $form, array &$form_state) {
     // The machine name field should already check to see if the requested
     // machine name is available. Regardless of machine_name or human readable
     // name, check to see if the provided pattern exists.
-    $format = trim($form_state['values']['date_format_pattern']);
-    $formats = $this->queryFactory
-      ->get($this->entity->entityType())
-      ->condition('pattern.' . $this->patternType, $format)
-      ->execute();
-
-    // Exclude the current format.
-    unset($formats[$this->entity->id()]);
-    if (!empty($formats)) {
-      form_set_error('date_format_pattern', t('This format already exists. Enter a unique format string.'));
+    $pattern = trim($form_state['values']['date_format_pattern']);
+    foreach ($this->dateFormatStorage->loadMultiple() as $format) {
+      if ($format->getPattern() == $pattern) {
+        form_set_error('date_format_pattern', t('This format already exists. Enter a unique format string.'));
+        continue;
+      }
     }
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/ConfigEntityQueryTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/ConfigEntityQueryTest.php
index 9a84de9..3926f29 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/ConfigEntityQueryTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/ConfigEntityQueryTest.php
@@ -110,7 +110,7 @@ protected function setUp() {
 
     $array['level1']['level2'] = 3;
     $entity = entity_create('config_query_test', array(
-      'label' => $this->randomName() . '_test_contains_' . $this->randomName(),
+      'label' => $this->randomName() . '_TEST_contains_' . $this->randomName(),
       'id' => '5',
       'number' => 53,
       'array' => $array,
@@ -462,6 +462,22 @@ protected function testDotted() {
   }
 
   /**
+   * Tests case sensitivity.
+   */
+  public function testCaseSensitivity() {
+    // Filter by label with a known containing case-sensitive word.
+    $this->queryResults = $this->factory->get('config_query_test')
+      ->condition('label', 'TEST', 'CONTAINS')
+      ->execute();
+    $this->assertResults(array('3', '4', '5'));
+
+    $this->queryResults = $this->factory->get('config_query_test')
+      ->condition('label', 'test', 'CONTAINS')
+      ->execute();
+    $this->assertResults(array('3', '4', '5'));
+  }
+
+  /**
    * Asserts the results as expected regardless of order.
    *
    * @param array $expected