diff --git a/src/Plugin/views/row/Calendar.php b/src/Plugin/views/row/Calendar.php
index 183c698..768957a 100644
--- a/src/Plugin/views/row/Calendar.php
+++ b/src/Plugin/views/row/Calendar.php
@@ -451,7 +451,7 @@ class Calendar extends RowPluginBase {
       // use $dateInfo to get field(s) used as arguments
       $entity_field_name = str_replace('_value', '', $dateInfo->getDateArgument()->realField);
       $field_definition = $entity->getFieldDefinition($entity_field_name);
-      if ($field_definition instanceof BaseFieldDefinition) {
+      if ($field_definition instanceof BaseFieldDefinition || $field_definition->getType() == "smartdate") {
         $storage_format = 'U';
       }
       else {