diff --git a/apps/contactsinteraction/lib/Card.php b/apps/contactsinteraction/lib/Card.php
index aa73d0e2122b8..590955104cbd2 100644
--- a/apps/contactsinteraction/lib/Card.php
+++ b/apps/contactsinteraction/lib/Card.php
@@ -99,7 +99,7 @@ public function getETag(): ?string {
 	 * @inheritDoc
 	 */
 	public function getSize(): int {
-		throw new NotImplemented();
+		return strlen($this->contact->getCard());
 	}
 
 	/**