diff --git a/src/cryptobox/core/tools.py b/src/cryptobox/core/tools.py
index 1aebd4e..0a28f6a 100644
--- a/src/cryptobox/core/tools.py
+++ b/src/cryptobox/core/tools.py
@@ -213,7 +213,7 @@ def is_part_of_blockdevice(parent, subdevice):
 
 
 def get_blockdevice_size(device):
-	"""Return the size of a blockdevice.
+	"""Return the size of a blockdevice in megabyte.
 	"""
 	if not device:
 		return -1
@@ -240,7 +240,7 @@ def get_blockdevice_size_humanly(device):
 	"""
 	size = get_blockdevice_size(device)
 	if size > 5120:
-		return "%sGB" % size/1024
+		return "%dGB" % int(size/1024)
 	else:
-		return "%sMB" % size
+		return "%dMB" % size