diff --git a/backend/app/coordinator/routes/groups.py b/backend/app/coordinator/routes/groups.py
index 0215303..b8a0905 100644
--- a/backend/app/coordinator/routes/groups.py
+++ b/backend/app/coordinator/routes/groups.py
@@ -38,24 +38,19 @@ def create_group(data: dict) -> dict:
     students_indexes = data['students']
     project_supervisor_id = data['project_supervisor_id']
 
-    # can assign a new group to project_supervisor
-
-    # nie działa to poprawnie
-    # result = db.session.query(ProjectSupervisor.count_groups - db.func.count(ProjectSupervisor.id)). \
-    #     join(Group).filter(ProjectSupervisor.id == project_supervisor_id). \
-    #     group_by(ProjectSupervisor.id).scalar()
-    
-    # if result is None:
-    #     abort(400, "Project Supervisor doesnt exist")
-    # elif result <= 0:
-    #     abort(400, "Can't create new group, project supervisor achieved a limit of groups")
-
     project_supervisor = ProjectSupervisor.query.filter_by(id=project_supervisor_id).first()
 
-    if project_supervisor is None: 
-        abort(400, "Project Supervisor with id {project_supervisor_id} doesnt exist")
-    elif project_supervisor.limit_group == project_supervisor.count_groups:
-         abort(400, "Can't create new group, project supervisor achieved a limit of groups")
+    if project_supervisor is None:
+        abort(400, f"Project Supervisor with id {project_supervisor_id} doesnt exist")
+    elif project_supervisor.limit_group < len(students_indexes):
+        abort(400, f"Too much students you want add to group, "
+                   f"this group can have only {project_supervisor.limit_group} students")
+
+    result = db.session.query(ProjectSupervisor.count_groups - db.func.count(ProjectSupervisor.id)).join(Group).filter(
+        ProjectSupervisor.id == project_supervisor_id).group_by(ProjectSupervisor.id).scalar()
+
+    if result is not None and result <= 0:
+        abort(400, "Can't create new group, project supervisor achieved a limit of groups")
 
     group = Group(name=name, project_supervisor_id=project_supervisor_id)