diff --git a/src/Controller/Booking/CreateStep1Controller.php b/src/Controller/Booking/CreateStep1Controller.php
index 5043a97..9f3ca9c 100644
--- a/src/Controller/Booking/CreateStep1Controller.php
+++ b/src/Controller/Booking/CreateStep1Controller.php
@@ -33,7 +33,7 @@ class CreateStep1Controller extends AbstractController
     public function index(Request $request): Response
     {
         $bookingCreateDto = $this->bookingService->getOrCreateBookingCreateDto($request);
-        $participantsCount = $this->bookingService->getParticipantsCount($bookingCreateDto->roomSelections, $bookingCreateDto->travel);
+        $summary = $this->bookingService->getRoomSummaryAndParticipantCount($bookingCreateDto);
 
         // Validate step access - allow step 1 or redirect to current step
         $this->validateStepAccess($bookingCreateDto, 1);
@@ -53,8 +53,33 @@ class CreateStep1Controller extends AbstractController
 
         return $this->render('booking/create_step_1.html.twig', [
             'bookingCreateDto' => $bookingCreateDto,
-            'participantsCount' => $participantsCount,
+            'roomSummary' => $summary['selectedRooms'],
+            'participantCount' => $summary['participantCount'],
             'form' => $form->createView(),
         ]);
     }
+
+    /**
+     * HTMX endpoint for live summary updates in step 1.
+     */
+    #[Route('/bookings/create/room-summary', name: 'app_booking_create_step_1_room_summary', methods: ['POST'])]
+    public function roomSummary(Request $request): Response
+    {
+        $bookingCreateDto = $this->bookingService->getOrCreateBookingCreateDto($request);
+
+        // Process the form to update the DTO with the latest room selection
+        $form = $this->createForm(BookingCreateStep1Type::class, $bookingCreateDto, [
+            'validation_groups' => false,
+        ]);
+        $form->handleRequest($request);
+
+        $this->bookingService->saveBookingCreateDto($request, $bookingCreateDto);
+
+        $summary = $this->bookingService->getRoomSummaryAndParticipantCount($bookingCreateDto);
+
+        return $this->render('booking/_room_summary.html.twig', [
+            'roomSummary' => $summary['selectedRooms'],
+            'participantCount' => $summary['participantCount'],
+        ]);
+    }
 }
diff --git a/src/Service/BookingService.php b/src/Service/BookingService.php
index 7f32b9e..21db560 100644
--- a/src/Service/BookingService.php
+++ b/src/Service/BookingService.php
@@ -120,4 +120,21 @@ class BookingService
 
         return $counts;
     }
+
+    /**
+     * Returns a summary of selected rooms and the resulting participant count for a booking.
+     *
+     * @param BookingCreateDto $bookingCreateDto
+     * @return array{selectedRooms: array, participantCount: int}
+     */
+    public function getRoomSummaryAndParticipantCount(BookingCreateDto $bookingCreateDto): array
+    {
+        $selectedRooms = $bookingCreateDto->getSelectedRooms();
+        $participantCount = $this->getParticipantsCount($selectedRooms, $bookingCreateDto->travel);
+
+        return [
+            'selectedRooms' => $selectedRooms,
+            'participantCount' => $participantCount,
+        ];
+    }
 }
diff --git a/templates/booking/_room_summary.html.twig b/templates/booking/_room_summary.html.twig
new file mode 100644
index 0000000..aeab0bc
--- /dev/null
+++ b/templates/booking/_room_summary.html.twig
@@ -0,0 +1,15 @@
+<div id="booking-summary">
+    <h3>Zusammenfassung</h3>
+    <h4>Zimmer</h4>
+    <ul class="list-disc list-inside pb-4">
+        {% for roomSelection in roomSummary %}
+            <li>
+                {{ roomSelection.quantity }} x {{ roomSelection.roomLabel }}
+            </li>
+        {% endfor %}
+    </ul>
+    <h4>Anzahl Teilnehmer</h4>
+    <p>
+        {{ participantCount }}
+    </p>
+</div> 
\ No newline at end of file
diff --git a/templates/booking/create_step_1.html.twig b/templates/booking/create_step_1.html.twig
index 3802763..5da51f9 100644
--- a/templates/booking/create_step_1.html.twig
+++ b/templates/booking/create_step_1.html.twig
@@ -7,7 +7,18 @@
         <div class="col-span-2">
             <h2>Zimmerauswahl</h2>
             {{ form_start(form) }}
-            {{ form_row(form.roomSelections) }}
+            <div>
+                {% for roomSelection in form.roomSelections %}
+                    {{ form_row(roomSelection, {
+                        'attr': {
+                            'hx-post': path('app_booking_create_step_1_room_summary'),
+                            'hx-target': '#booking-summary',
+                            'hx-swap': 'outerHTML',
+                            'hx-trigger': 'change'
+                        }
+                    }) }}
+                {% endfor %}
+            </div>
             <div class="flex justify-end">
                 <button type="submit" class="button bg-button bg-button--secondary">Weiter</button>
             </div>
@@ -15,13 +26,7 @@
             {{ form_end(form) }}
         </div>
         <div>
-            <h3>Zusammenfassung</h3>
-            <p>Reise: {{ bookingCreateDto.travel.label }}</p>
-            <p>Datum: {{ bookingCreateDto.travel.dateFrom | date('d.m.Y') }} - {{ bookingCreateDto.travel.dateTo | date('d.m.Y') }}</p>
-            <p>Hotel: {{ bookingCreateDto.travel.hotel.name }}</p>
-            {% if participantsCount > 0 %}
-                <p>Teilnehmerzahl: {{ participantsCount }}</p>
-            {% endif %}
+            {% include 'booking/_room_summary.html.twig' %}
         </div>
     </div>
 {% endblock %}