diff --git a/grudge/dt_utils.py b/grudge/dt_utils.py
index 4c477216979deab22139cd6490c6887e078013a4..b41c683cd2c9acdf3cc5a5fbf080a33cae7c1e4f 100644
--- a/grudge/dt_utils.py
+++ b/grudge/dt_utils.py
@@ -266,7 +266,8 @@ def dt_geometric_factors(
     )
 
     if dcoll.dim == 1:
-        return freeze(cell_vols)
+        # Inscribed "circle" radius is half the cell size
+        return freeze(cell_vols/2)
 
     dd_face = DOFDesc("all_faces", dd.discretization_tag)
     face_discr = dcoll.discr_from_dd(dd_face)