diff --git a/kademlia/routing.py b/kademlia/routing.py
index 0f9aa4c..c047025 100644
--- a/kademlia/routing.py
+++ b/kademlia/routing.py
@@ -4,7 +4,7 @@ import operator
 import asyncio
 
 from collections import OrderedDict
-from kademlia.utils import OrderedSet, sharedPrefix
+from kademlia.utils import OrderedSet, sharedPrefix, bytesToBitString
 
 
 class KBucket(object):
@@ -65,7 +65,7 @@ class KBucket(object):
         return True
 
     def depth(self):
-        sp = sharedPrefix([n.id for n in self.nodes.values()])
+        sp = sharedPrefix([bytesToBitString(n.id) for n in self.nodes.values()])
         return len(sp)
 
     def head(self):
diff --git a/kademlia/utils.py b/kademlia/utils.py
index 7528703..45d646e 100644
--- a/kademlia/utils.py
+++ b/kademlia/utils.py
@@ -49,3 +49,8 @@ def sharedPrefix(args):
             break
         i += 1
     return args[0][:i]
+
+
+def bytesToBitString(bytes):
+    bits = [bin(byte)[2:].rjust(8, '0') for byte in bytes]
+    return "".join(bits)