diff --git a/tools/zookeeper/power_monitor.py b/tools/zookeeper/power_monitor.py
index d3bdd6679..f88741813 100755
--- a/tools/zookeeper/power_monitor.py
+++ b/tools/zookeeper/power_monitor.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 import sys
 import time
+import datetime
 
 from common.realtime import Ratekeeper
 from common.filter_simple import FirstOrderFilter
@@ -19,12 +20,19 @@ if __name__ == "__main__":
   rk = Ratekeeper(rate, print_delay_threshold=None)
   fltr = FirstOrderFilter(0, 5, 1. / rate, initialized=False)
 
+  measurements = []
+  start_time = time.monotonic()
+
   try:
-    start_time = time.monotonic()
     while duration is None or time.monotonic() - start_time < duration:
       fltr.update(z.read_power())
       if rk.frame % rate == 0:
         print(f"{fltr.x:.2f} W")
+        measurements.append(fltr.x)
       rk.keep_time()
   except KeyboardInterrupt:
     pass
+
+  t = datetime.timedelta(seconds=time.monotonic() - start_time)
+  avg = sum(measurements) / len(measurements)
+  print(f"\nAverage power: {avg:.2f}W over {t}")