diff --git a/.plans/open/issue-201-count-archived-loads-all-members.md b/.plans/done/issue-201-count-archived-loads-all-members.md
similarity index 100%
rename from .plans/open/issue-201-count-archived-loads-all-members.md
rename to .plans/done/issue-201-count-archived-loads-all-members.md
diff --git a/lib/Db/MemberMapper.php b/lib/Db/MemberMapper.php
index d9f5edb..3840a8b 100644
--- a/lib/Db/MemberMapper.php
+++ b/lib/Db/MemberMapper.php
@@ -372,6 +372,29 @@ class MemberMapper extends QBMapper {
         return $count;
     }
 
+    /**
+     * Count all soft-deleted (archived) members.
+     *
+     * Uses a single SQL COUNT query instead of loading all members
+     * into memory.
+     *
+     * Part of Issue #201.
+     *
+     * @throws Exception
+     */
+    public function countArchived(): int {
+        $qb = $this->db->getQueryBuilder();
+        $qb->select($qb->createFunction('COUNT(*)'))
+            ->from($this->getTableName())
+            ->where($qb->expr()->isNotNull('deleted_at'));
+
+        $result = $qb->executeQuery();
+        $count = (int)$result->fetchOne();
+        $result->closeCursor();
+
+        return $count;
+    }
+
     // ── Joined fetch methods (N+1 avoidance) ────────────────────────
 
     /**
diff --git a/lib/Service/MemberService.php b/lib/Service/MemberService.php
index 895d8f8..91eab68 100644
--- a/lib/Service/MemberService.php
+++ b/lib/Service/MemberService.php
@@ -761,11 +761,13 @@ class MemberService {
     /**
      * Count all soft-deleted (archived) members.
      *
+     * Part of Issue #201: uses a single SQL COUNT query via the mapper
+     * instead of loading all members into memory.
+     *
      * @throws Exception
      */
     public function countArchived(): int {
-        $allMembers = $this->memberMapper->findAll(null, null, true);
-        return count(array_filter($allMembers, fn(Member $m) => $m->getDeletedAt() !== null));
+        return $this->memberMapper->countArchived();
     }
 
     /**
diff --git a/tests/Unit/MapperTest.php b/tests/Unit/MapperTest.php
index be5af8e..6531a9e 100644
--- a/tests/Unit/MapperTest.php
+++ b/tests/Unit/MapperTest.php
@@ -543,6 +543,20 @@ class MapperTest extends TestCase {
         $this->assertSame(0, $count);
     }
 
+    public function testMemberMapperCountArchived(): void {
+        $this->configureResultCount(7);
+        $mapper = new MemberMapper($this->db);
+        $count = $mapper->countArchived();
+        $this->assertSame(7, $count);
+    }
+
+    public function testMemberMapperCountArchivedZero(): void {
+        $this->configureResultCount(0);
+        $mapper = new MemberMapper($this->db);
+        $count = $mapper->countArchived();
+        $this->assertSame(0, $count);
+    }
+
     // ══════════════════════════════════════════════════════════════════
     // ── FamilyMapper ─────────────────────────────────────────────────
     // ══════════════════════════════════════════════════════════════════
diff --git a/tests/Unit/MemberServiceTest.php b/tests/Unit/MemberServiceTest.php
index 968eb9c..1458de1 100644
--- a/tests/Unit/MemberServiceTest.php
+++ b/tests/Unit/MemberServiceTest.php
@@ -1299,17 +1299,19 @@ class MemberServiceTest extends TestCase {
     // ── countArchived() ──────────────────────────────────────────────
 
     public function testCountArchivedReturnsCorrectCount(): void {
-        $activeMember = $this->createMember(1);
-        $deletedMember = $this->createMember(2);
-        $deletedMember->setDeletedAt('2026-01-01 00:00:00');
-
-        $this->memberMapper->method('findAll')
-            ->with(null, null, true)
-            ->willReturn([$activeMember, $deletedMember]);
+        // Issue #201: countArchived() now delegates to MemberMapper::countArchived()
+        // which uses a SQL COUNT query instead of loading all members into memory.
+        $this->memberMapper->method('countArchived')->willReturn(1);
 
         $this->assertSame(1, $this->service->countArchived());
     }
 
+    public function testCountArchivedReturnsZeroWhenNoArchived(): void {
+        $this->memberMapper->method('countArchived')->willReturn(0);
+
+        $this->assertSame(0, $this->service->countArchived());
+    }
+
     // ── Joined methods: findAllWithRelations ──────────────────────
 
     public function testFindAllWithRelationsReturnsMemberWithNestedSubEntities(): void {