diff --git a/pintless/default_units.json b/pintless/default_units.json
index 8a66de3..6154cd9 100755
--- a/pintless/default_units.json
+++ b/pintless/default_units.json
@@ -69,7 +69,8 @@
     },
 
     "dimensionless": {
-        "dimensionless": 1
+        "dimensionless": 1,
+        "bool": 1
     },
 
     "length": {