diff --git a/specs/light_client/merkle_proofs.md b/specs/light_client/merkle_proofs.md
index 2e00806ee..469f347ac 100644
--- a/specs/light_client/merkle_proofs.md
+++ b/specs/light_client/merkle_proofs.md
@@ -153,7 +153,7 @@ def get_generalized_index_length(index: GeneralizedIndex) -> int:
    """
    Returns the length of a path represented by a generalized index.
    """
-   return log(index)
+   return log2(index)
 ```
 
 #### `get_generalized_index_bit`