diff --git a/i3pystatus/mem.py b/i3pystatus/mem.py
index 13340a0..cdf47e3 100644
--- a/i3pystatus/mem.py
+++ b/i3pystatus/mem.py
@@ -16,8 +16,8 @@ class Mem(IntervalModule):
     Requires psutil (from PyPI)
     """
 
-    format = "{avail_mem} GB"
-    divisor = 1024 ** 3
+    format = "{avail_mem} MiB"
+    divisor = 1024 ** 2
     color = "#00FF00"
     warn_color = "#FFFF00"
     alert_color = "#FF0000"