diff --git a/kennitala/__init__.py b/kennitala/__init__.py
index 34a61e9..5f9afd4 100644
--- a/kennitala/__init__.py
+++ b/kennitala/__init__.py
@@ -127,7 +127,7 @@ def validate(self):
         if not self.kennitala:
             return False
 
-        pattern = r'\d{6}\-?\d{4}'
+        pattern = r'\d{6}\-?\d{4}\b'
         if not re.match(pattern, self.kennitala):
             return False
 
diff --git a/tests/test_kennitala.py b/tests/test_kennitala.py
index 8194d14..8331887 100644
--- a/tests/test_kennitala.py
+++ b/tests/test_kennitala.py
@@ -21,6 +21,7 @@
     '0503760647',
     '550376',
     '1405433219',
+    '28129420229',
 )