diff --git a/src/db/db/dbNetlist.cc b/src/db/db/dbNetlist.cc
index 1f740ef0f..392814066 100644
--- a/src/db/db/dbNetlist.cc
+++ b/src/db/db/dbNetlist.cc
@@ -851,6 +851,21 @@ void Circuit::connect_pin (size_t pin_id, Net *net)
   }
 }
 
+bool Circuit::is_external_net (const db::Net *net) const
+{
+  if (!net || net->pin_count () == 0) {
+    return false;
+  }
+
+  for (std::vector<Net::pin_iterator>::const_iterator p = m_pin_refs.begin (); p != m_pin_refs.end (); ++p) {
+    if (*p != Net::pin_iterator () && (*p)->net () == net) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void Circuit::purge_nets ()
 {
   std::vector<db::Net *> nets_to_be_purged;
diff --git a/src/db/db/dbNetlist.h b/src/db/db/dbNetlist.h
index b1b627ffc..54b6a5ab1 100644
--- a/src/db/db/dbNetlist.h
+++ b/src/db/db/dbNetlist.h
@@ -1518,6 +1518,13 @@ public:
    */
   void connect_pin (size_t pin_id, Net *net);
 
+  /**
+   *  @brief Returns true, if the net is an external net
+   *
+   *  External nets are net which are connected to an outgoing pin.
+   */
+  bool is_external_net (const db::Net *net) const;
+
   /**
    *  @brief Purge unused nets
    *
diff --git a/src/db/db/gsiDeclDbNetlist.cc b/src/db/db/gsiDeclDbNetlist.cc
index 194ad572e..f644ca07f 100644
--- a/src/db/db/gsiDeclDbNetlist.cc
+++ b/src/db/db/gsiDeclDbNetlist.cc
@@ -760,6 +760,10 @@ Class<db::Circuit> decl_dbCircuit ("db", "Circuit",
     "@brief Gets the cell index of the circuit\n"
     "See \\cell_index= for details.\n"
   ) +
+  gsi::method ("is_external_net?", &db::Circuit::is_external_net, gsi::arg ("net"),
+    "@brief Returns true, if the given net is an external one.\n"
+    "External nets are nets which are connected to an outgoing pin."
+  ) +
   gsi::method ("net_for_pin", (db::Net *(db::Circuit::*) (size_t)) &db::Circuit::net_for_pin, gsi::arg ("pin_id"),
     "@brief Gets the net object attached to a specific pin.\n"
     "This is the net object inside the circuit which attaches to the given outward-bound pin.\n"
diff --git a/src/db/unit_tests/dbLayoutToNetlistTests.cc b/src/db/unit_tests/dbLayoutToNetlistTests.cc
index bebbd6e0c..f450c71a9 100644
--- a/src/db/unit_tests/dbLayoutToNetlistTests.cc
+++ b/src/db/unit_tests/dbLayoutToNetlistTests.cc
@@ -144,11 +144,7 @@ static void dump_recursive_nets_to_layout (const db::LayoutToNetlist &l2n, db::L
     for (db::Circuit::const_net_iterator n = c->begin_nets (); n != c->end_nets (); ++n) {
 
       //  only handle nets without outgoing pins - these are local
-      bool is_local = true;
-      for (db::Net::const_pin_iterator p = n->begin_pins (); p != n->end_pins () && is_local; ++p) {
-        is_local = (p->subcircuit () != 0);
-      }
-      if (! is_local) {
+      if (c->is_external_net (n.operator-> ())) {
         continue;
       }
 
diff --git a/src/db/unit_tests/dbNetlistTests.cc b/src/db/unit_tests/dbNetlistTests.cc
index ad9ab0407..74e4d2acc 100644
--- a/src/db/unit_tests/dbNetlistTests.cc
+++ b/src/db/unit_tests/dbNetlistTests.cc
@@ -751,18 +751,21 @@ TEST(8_NetSubCircuitsEditing)
   n2->set_name ("n2");
   c.add_net (n2);
 
+  EXPECT_EQ (c.is_external_net (n1), false);
   c.connect_pin (0, n1);
 
   EXPECT_EQ (n1->terminal_count (), size_t (0));
   EXPECT_EQ (n1->pin_count (), size_t (1));
   EXPECT_EQ (n1->is_floating (), true);
   EXPECT_EQ (n1->is_internal (), false);
+  EXPECT_EQ (c.is_external_net (n1), true);
 
   EXPECT_EQ (c.net_for_pin (0), n1);
   EXPECT_EQ (c.net_for_pin (1), 0);
 
   sc1->connect_pin (0, n1);
   sc1->connect_pin (1, n2);
+  EXPECT_EQ (c.is_external_net (n2), false);
 
   EXPECT_EQ (n1->terminal_count (), size_t (0));
   EXPECT_EQ (n1->pin_count (), size_t (2));
diff --git a/testdata/ruby/dbNetlist.rb b/testdata/ruby/dbNetlist.rb
index 214983856..39c85f047 100644
--- a/testdata/ruby/dbNetlist.rb
+++ b/testdata/ruby/dbNetlist.rb
@@ -510,7 +510,9 @@ class DBNetlist_TestClass < TestBase
     c.each_net { |n| names << n.name }
     assert_equal(names, [ "NET1", "NET2" ])
 
+    assert_equal(c.is_external_net?(net1), false)
     c.connect_pin(pina1, net1)
+    assert_equal(c.is_external_net?(net1), true)
     c.connect_pin(pinb1.id, net1)
     c.connect_pin(pina2, net2)
     c.connect_pin(pinb2.id, net2)