diff --git a/apps/schedule/schedule_xml.py b/apps/schedule/schedule_xml.py
index ec104ee37..c06b966e4 100644
--- a/apps/schedule/schedule_xml.py
+++ b/apps/schedule/schedule_xml.py
@@ -17,7 +17,11 @@ def get_duration(start_time, end_time):
     duration = (end_time - start_time).total_seconds() / 60
     hours = int(duration // 60)
     minutes = int(duration % 60)
-    return "{0:01d}:{1:02d}".format(hours, minutes)
+    if hours < 24:
+        return f"{hours:d}:{minutes:02d}"
+    days = int(hours // 24)
+    hours = int(hours % 24)
+    return f"{days:d}:{hours:02d}:{minutes:02d}"
 
 
 def get_day_start_end(dt, start_time=time(4, 0)):
diff --git a/tests/test_schedule.py b/tests/test_schedule.py
new file mode 100644
index 000000000..18550113b
--- /dev/null
+++ b/tests/test_schedule.py
@@ -0,0 +1,20 @@
+from datetime import datetime
+
+import pytest
+
+from apps.schedule import schedule_xml
+
+
+@pytest.mark.parametrize('start_time, end_time, expected', [
+    ('2024-01-01 00:00:00', '2024-01-01 00:01:00', '0:01'),
+    ('2024-01-01 00:00:00', '2024-01-01 00:01:45', '0:01'),
+    ('2024-01-01 00:00:00', '2024-01-01 01:00:00', '1:00'),
+    ('2024-01-01 00:00:00', '2024-01-01 12:00:00', '12:00'),
+    ('2024-01-01 00:00:00', '2024-01-02 00:00:00', '1:00:00'),
+    ('2024-01-01 00:00:00', '2024-01-02 12:34:00', '1:12:34'),
+])
+def test_get_duration(start_time, end_time, expected):
+    fmt = '%Y-%m-%d %H:%M:%S'
+    start_time = datetime.strptime(start_time, fmt)
+    end_time = datetime.strptime(end_time, fmt)
+    assert schedule_xml.get_duration(start_time, end_time) == expected