diff --git a/prjxray/tile.py b/prjxray/tile.py
index 4ca5a702..380bc1bb 100644
--- a/prjxray/tile.py
+++ b/prjxray/tile.py
@@ -134,7 +134,7 @@ class SitePin(namedtuple('SitePin', 'name wire timing')):
 WireInfo = namedtuple('WireInfo', 'pips sites')
 
 # Conversion factor from database to internal units.
-RESISTANCE_FACTOR = 1
+RESISTANCE_FACTOR = 1e3
 CAPACITANCE_FACTOR = 1e3