diff --git a/apps/files_trashbin/lib/Trashbin.php b/apps/files_trashbin/lib/Trashbin.php
index db6fa35e85..d6c0644cce 100644
--- a/apps/files_trashbin/lib/Trashbin.php
+++ b/apps/files_trashbin/lib/Trashbin.php
@@ -708,11 +708,13 @@ class Trashbin {
 	 */
 	private static function calculateFreeSpace($trashbinSize, $user) {
 		$config = \OC::$server->getConfig();
-		$systemTrashbinSize = (int)$config->getAppValue('files_trashbin', 'trashbin_size', '-1');
 		$userTrashbinSize = (int)$config->getUserValue($user, 'files_trashbin', 'trashbin_size', '-1');
-		$configuredTrashbinSize = ($userTrashbinSize < 0) ? $systemTrashbinSize : $userTrashbinSize;
-		if ($configuredTrashbinSize) {
-			return $configuredTrashbinSize - $trashbinSize;
+		if ($userTrashbinSize > -1) {
+			return $userTrashbinSize - $trashbinSize;
+		}
+		$systemTrashbinSize = (int)$config->getAppValue('files_trashbin', 'trashbin_size', '-1');
+		if ($systemTrashbinSize > -1) {
+			return $systemTrashbinSize - $trashbinSize;
 		}
 
 		$softQuota = true;