diff --git a/src/Repository/ClientTicketRepository.php b/src/Repository/ClientTicketRepository.php
new file mode 100644
index 0000000..3f661b7
--- /dev/null
+++ b/src/Repository/ClientTicketRepository.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Repository;
+
+use App\Entity\ClientTicket;
+use App\Entity\Project;
+use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Doctrine\Persistence\ManagerRegistry;
+
+/**
+ * @extends ServiceEntityRepository<ClientTicket>
+ */
+class ClientTicketRepository extends ServiceEntityRepository
+{
+    public function __construct(ManagerRegistry $registry)
+    {
+        parent::__construct($registry, ClientTicket::class);
+    }
+
+    public function findNextNumberForProject(Project $project): int
+    {
+        $result = $this->createQueryBuilder('ct')
+            ->select('MAX(ct.number)')
+            ->where('ct.project = :project')
+            ->setParameter('project', $project)
+            ->getQuery()
+            ->getSingleScalarResult()
+        ;
+
+        return ((int) $result) + 1;
+    }
+}