diff --git a/src/py/mat3ra/code/constants.py b/src/py/mat3ra/code/constants.py
index 5081fe6..a47976a 100644
--- a/src/py/mat3ra/code/constants.py
+++ b/src/py/mat3ra/code/constants.py
@@ -2,6 +2,8 @@
 
 from mat3ra.esse.models.definitions.constants import FundamentalConstants
 
+HASH_TOLERANCE = 3  # decimal places; mirrors @mat3ra/code/dist/js/constants.ts HASH_TOLERANCE
+
 CONSTANTS = FundamentalConstants()