diff --git a/src/libsysprof-analyze/sysprof-document-counter-private.h b/src/libsysprof-analyze/sysprof-document-counter-private.h
index 821d2bbc..b76ee679 100644
--- a/src/libsysprof-analyze/sysprof-document-counter-private.h
+++ b/src/libsysprof-analyze/sysprof-document-counter-private.h
@@ -24,11 +24,12 @@
 
 G_BEGIN_DECLS
 
-SysprofDocumentCounter *_sysprof_document_counter_new (guint       id,
-                                                       guint       type,
-                                                       GRefString *category,
-                                                       GRefString *name,
-                                                       GRefString *description,
-                                                       GArray     *values);
+SysprofDocumentCounter *_sysprof_document_counter_new             (guint                   id,
+                                                                   guint                   type,
+                                                                   GRefString             *category,
+                                                                   GRefString             *name,
+                                                                   GRefString             *description,
+                                                                   GArray                 *values);
+void                    _sysprof_document_counter_calculate_range (SysprofDocumentCounter *self);
 
 G_END_DECLS
diff --git a/src/libsysprof-analyze/sysprof-document-counter.c b/src/libsysprof-analyze/sysprof-document-counter.c
index 5487088c..ccced724 100644
--- a/src/libsysprof-analyze/sysprof-document-counter.c
+++ b/src/libsysprof-analyze/sysprof-document-counter.c
@@ -206,47 +206,6 @@ _sysprof_document_counter_new (guint       id,
   self->description = description;
   self->values = values;
 
-  if (type == SYSPROF_CAPTURE_COUNTER_DOUBLE)
-    {
-      double min_value = 0;
-      double max_value = 0;
-
-      for (guint i = 0; i < values->len; i++)
-        {
-          const SysprofDocumentTimedValue *value = &g_array_index (self->values, SysprofDocumentTimedValue, i);
-          double v = value->v_double;
-
-          if (v < min_value)
-            min_value = v;
-
-          if (v > max_value)
-            max_value = v;
-        }
-
-      self->min_value = min_value;
-      self->max_value = max_value;
-    }
-  else if (type == SYSPROF_CAPTURE_COUNTER_INT64)
-    {
-      gint64 min_value = 0;
-      gint64 max_value = 0;
-
-      for (guint i = 0; i < values->len; i++)
-        {
-          const SysprofDocumentTimedValue *value = &g_array_index (self->values, SysprofDocumentTimedValue, i);
-          gint64 v = value->v_int64;
-
-          if (v < min_value)
-            min_value = v;
-
-          if (v > max_value)
-            max_value = v;
-        }
-
-      self->min_value = min_value;
-      self->max_value = max_value;
-    }
-
   return self;
 }
 
@@ -353,3 +312,59 @@ sysprof_document_counter_get_value_double (SysprofDocumentCounter *self,
 
   return g_array_index (self->values, SysprofDocumentTimedValue, nth).v_double;
 }
+
+static inline double
+value_as_double (guint                            type,
+                 const SysprofDocumentTimedValue *value)
+{
+  if (type == SYSPROF_CAPTURE_COUNTER_DOUBLE)
+    return value->v_double;
+  else if (type == SYSPROF_CAPTURE_COUNTER_INT64)
+    return value->v_int64;
+  else
+    return .0;
+}
+
+void
+_sysprof_document_counter_calculate_range (SysprofDocumentCounter *self)
+{
+  const SysprofDocumentTimedValue *values;
+  gboolean min_value_changed = FALSE;
+  gboolean max_value_changed = FALSE;
+  double min_value;
+  double max_value;
+  guint n_values;
+
+  g_return_if_fail (SYSPROF_IS_DOCUMENT_COUNTER (self));
+
+  if (self->values->len == 0)
+    return;
+
+  values = &g_array_index (self->values, SysprofDocumentTimedValue, 0);
+  n_values = self->values->len;
+
+  min_value = value_as_double (self->type, &values[0]);
+  max_value = min_value;
+
+  for (guint i = 1; i < n_values; i++)
+    {
+      double value = value_as_double (self->type, &values[i]);
+
+      min_value = MIN (min_value, value);
+      max_value = MAX (max_value, value);
+    }
+
+  min_value_changed = self->min_value != min_value;
+  max_value_changed = self->max_value != max_value;
+
+  self->min_value = min_value;
+  self->max_value = max_value;
+
+  if (min_value_changed)
+    g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MIN_VALUE]);
+
+  if (max_value_changed)
+    g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MAX_VALUE]);
+
+  g_print ("%s %lf..%lf\n", self->name, self->min_value, self->max_value);
+}
diff --git a/src/libsysprof-analyze/sysprof-document.c b/src/libsysprof-analyze/sysprof-document.c
index def8fa8f..1d974c6e 100644
--- a/src/libsysprof-analyze/sysprof-document.c
+++ b/src/libsysprof-analyze/sysprof-document.c
@@ -588,6 +588,7 @@ sysprof_document_load_counters (SysprofDocument *self)
   g_autoptr(EggBitset) swap_ids = NULL;
   GListModel *model;
   EggBitsetIter iter;
+  guint n_counters;
   guint i;
 
   g_assert (SYSPROF_IS_DOCUMENT (self));
@@ -613,7 +614,8 @@ sysprof_document_load_counters (SysprofDocument *self)
       do
         {
           g_autoptr(SysprofDocumentCtrdef) ctrdef = g_list_model_get_item (model, i);
-          guint n_counters = sysprof_document_ctrdef_get_n_counters (ctrdef);
+
+          n_counters = sysprof_document_ctrdef_get_n_counters (ctrdef);
 
           for (guint j = 0; j < n_counters; j++)
             {
@@ -679,11 +681,23 @@ sysprof_document_load_counters (SysprofDocument *self)
                 }
 
               if ((values = g_hash_table_lookup (self->counter_id_to_values, GUINT_TO_POINTER (id))))
+              {
+                g_print ("Adding counter to %d\n", id);
                 g_array_append_val (values, ctrval);
+              }
             }
         }
       while (egg_bitset_iter_next (&iter, &i));
     }
+
+  n_counters = g_list_model_get_n_items (G_LIST_MODEL (self->counters));
+
+  for (i = 0; i < n_counters; i++)
+    {
+      g_autoptr(SysprofDocumentCounter) counter = g_list_model_get_item (G_LIST_MODEL (self->counters), i);
+
+      _sysprof_document_counter_calculate_range (counter);
+    }
 }
 
 static inline gboolean