diff -u b/core/modules/field_ui/src/Form/FieldStorageConfigEditForm.php b/core/modules/field_ui/src/Form/FieldStorageConfigEditForm.php
--- b/core/modules/field_ui/src/Form/FieldStorageConfigEditForm.php
+++ b/core/modules/field_ui/src/Form/FieldStorageConfigEditForm.php
@@ -117,8 +117,8 @@
     );
     $form['cardinality_container']['cardinality_number'] = array(
       '#type' => 'number',
-      '#description' => ($highest_delta > 1) ? $this->t("Minimum is !min, as there is data for this field.", ['!min' => $highest_delta]) : '',
-      '#default_value' => $cardinality != FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED ? $cardinality : 1,
+      '#description' => ($highest_delta > 1) ? $this->t("Minimum is @min, as there is data for this field.", ['@min' => $highest_delta]) : '',
+      '#default_value' => $cardinality != FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED ? $cardinality : $highest_delta,
       '#min' => $highest_delta,
       '#title' => $this->t('Limit'),
       '#title_display' => 'invisible',
@@ -162,7 +162,7 @@
       // Increment by one, since delta starts from 0.
       $highest_delta = $this->entity->getHighestDelta() + 1;
       if ($highest_delta > $form_state->getValue('cardinality_number')) {
-        $form_state->setErrorByName('cardinality_number', $this->t('You can not set the cardinality lower than @delta', array('@delta' => $highest_delta)));
+        $form_state->setErrorByName('cardinality_number', $this->t('You can not set the cardinality lower than @delta', ['@delta' => $highest_delta]));
       }
     }
   }
diff -u b/core/modules/field_ui/src/Tests/ManageFieldsTest.php b/core/modules/field_ui/src/Tests/ManageFieldsTest.php
--- b/core/modules/field_ui/src/Tests/ManageFieldsTest.php
+++ b/core/modules/field_ui/src/Tests/ManageFieldsTest.php
@@ -273,21 +273,19 @@
     $this->assertLinkByHref($field_edit_path);
 
     // Add two entries in the body.
-    $edit = array('title[0][value]' => 'Cardinality', 'body[0][value]' => 'Body 1', 'body[1][value]' => 'Body 2');
+    $edit = ['title[0][value]' => 'Cardinality', 'body[0][value]' => 'Body 1', 'body[1][value]' => 'Body 2'];
     $this->drupalPostForm('node/add/article', $edit, 'Save');
     $parts = explode('/', $this->getUrl());
     $nid = array_pop($parts);
 
     // Assert that you can't set the cardinality to a lower number then the
     // highest delta of this field.
-    $edit = array(
+    $edit = [
       'cardinality' => 'number',
       'cardinality_number' => 1,
-    );
+    ];
     $this->drupalPostForm($field_edit_path, $edit, t('Save field settings'));
-    $this->assertText('You can not set the cardinality lower than 2');
-    $this->drupalPostForm('node/' . $nid . '/edit', array(), 'Save');
-    $this->assertText('Body 2');
+    $this->assertRaw(t('Cardinality must be higher than or equal to %minimum.', ['%minimum' => 2]), 'Correctly failed to set cardinality lower than highest delta.');
 
     // Set to unlimited.
     $edit = array(
@@ -299,18 +297,16 @@
     $this->assertFieldByXPath("//select[@name='cardinality']", FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED);
     $this->assertFieldByXPath("//input[@name='cardinality_number']", 1);
 
-    $edit = array('title[0][value]' => 'Cardinality', 'body[0][value]' => 'Body 1', 'body[1][value]' => 'Body 2');
+    $edit = ['title[0][value]' => 'Cardinality', 'body[0][value]' => 'Body 1', 'body[1][value]' => 'Body 2'];
     $this->drupalPostForm('node/' . $nid . '/edit', $edit, 'Save');
     // Assert that you can't set the cardinality to a lower number then the
     // highest delta of this field.
-    $edit = array(
+    $edit = [
       'cardinality' => 'number',
       'cardinality_number' => 1,
-    );
+    ];
     $this->drupalPostForm($field_edit_path, $edit, t('Save field settings'));
-    $this->assertText('You can not set the cardinality lower than 2');
-    $this->drupalPostForm('node/' . $nid . '/edit', array(), 'Save');
-    $this->assertText('Body 2');
+    $this->assertRaw(t('Cardinality must be higher than or equal to %minimum.', ['%minimum' => 2]), 'Correctly failed to set cardinality lower than highest delta.');
   }
 
   /**