diff --git a/pyerrors/input/json.py b/pyerrors/input/json.py
index 45e6daa0..ebef1562 100644
--- a/pyerrors/input/json.py
+++ b/pyerrors/input/json.py
@@ -420,7 +420,7 @@ def _parse_json_dict(json_dict, verbose=True, full_output=False):
         elif io['type'] == 'Corr':
             ol.append(get_Corr_from_dict(io))
         else:
-            raise Exception("Unkown datatype.")
+            raise Exception("Unknown datatype.")
 
     if full_output:
         retd = {}