diff --git a/python/dune/perftool/pdelab/driver/timings.py b/python/dune/perftool/pdelab/driver/timings.py
index e78908252a0ee265e40b952dba7ad718b41bb2fd..3b9e353b4f794f843f010e083720d62061e03520 100644
--- a/python/dune/perftool/pdelab/driver/timings.py
+++ b/python/dune/perftool/pdelab/driver/timings.py
@@ -11,6 +11,7 @@ from dune.perftool.pdelab.driver import (get_formdata,
                                          name_initree,
                                          name_mpihelper,
                                          )
+from dune.perftool.pdelab.driver.constraints import name_assembled_constraints
 from dune.perftool.pdelab.driver.gridfunctionspace import (name_trial_gfs,
                                                            )
 from dune.perftool.pdelab.driver.gridoperator import (name_gridoperator,
@@ -37,11 +38,13 @@ def name_timing_identifier():
 @preamble
 def dump_dof_numbers(stream):
     ident = name_timing_identifier()
+    cc = name_assembled_constraints()
     level = get_option("instrumentation_level")
-    return "{} << \"{} \" << {} << \" dofs dofs \" << {}.size() << std::endl;".format(stream,
-                                                                                      level,
-                                                                                      ident,
-                                                                                      name_trial_gfs())
+    return "{} << \"{} \" << {} << \" dofs dofs \" << {}.size() - {}.size() << std::endl;".format(stream,
+                                                                                                  level,
+                                                                                                  ident,
+                                                                                                  name_trial_gfs(),
+                                                                                                  cc)
 
 
 @preamble