diff --git a/compiler/base/contact.py b/compiler/base/contact.py
index a2758c56..db415179 100644
--- a/compiler/base/contact.py
+++ b/compiler/base/contact.py
@@ -172,5 +172,5 @@ active = contact(layer_stack=("active", "contact", "poly"))
 poly = contact(layer_stack=("poly", "contact", "metal1"))
 m1m2 = contact(layer_stack=("metal1", "via1", "metal2"))
 m2m3 = contact(layer_stack=("metal2", "via2", "metal3"))
-#m3m4 = contact(layer_stack=("metal3", "via3", "metal4"))
+m3m4 = contact(layer_stack=("metal3", "via3", "metal4"))
 
diff --git a/compiler/base/design.py b/compiler/base/design.py
index 51994275..43957cb6 100644
--- a/compiler/base/design.py
+++ b/compiler/base/design.py
@@ -22,9 +22,7 @@ class design(hierarchy_design):
 
         self.m1_pitch = max(contact.m1m2.width,contact.m1m2.height) + max(self.m1_space, self.m2_space)
         self.m2_pitch = max(contact.m2m3.width,contact.m2m3.height) + max(self.m2_space, self.m3_space)
-        # SCMOS doesn't have m4...
-        #self.m3_pitch = max(contact.m3m4.width,contact.m3m4.height) + max(self.m3_space, self.m4_space)
-        self.m3_pitch = self.m2_pitch
+        self.m3_pitch = max(contact.m3m4.width,contact.m3m4.height) + max(self.m3_space, self.m4_space)
 
     def setup_drc_constants(self):
         """ These are some DRC constants used in many places in the compiler."""
@@ -38,6 +36,8 @@ class design(hierarchy_design):
         self.m2_space = drc("metal2_to_metal2")        
         self.m3_width = drc("minwidth_metal3")
         self.m3_space = drc("metal3_to_metal3")
+        self.m4_width = drc("minwidth_metal4")
+        self.m4_space = drc("metal4_to_metal4")
         self.active_width = drc("minwidth_active")
         self.active_space = drc("active_to_body_active")
         self.contact_width = drc("minwidth_contact")