diff --git a/swift/common/ring/ring.py b/swift/common/ring/ring.py
index 99370fd284..68635acd67 100644
--- a/swift/common/ring/ring.py
+++ b/swift/common/ring/ring.py
@@ -36,6 +36,8 @@ from swift.common.ring.utils import tiers_for_dev
 
 
 def calc_replica_count(replica2part2dev_id):
+    if not replica2part2dev_id:
+        return 0
     base = len(replica2part2dev_id) - 1
     extra = 1.0 * len(replica2part2dev_id[-1]) / len(replica2part2dev_id[0])
     return base + extra
diff --git a/test/unit/common/ring/test_builder.py b/test/unit/common/ring/test_builder.py
index b9421b3043..6d96a321a1 100644
--- a/test/unit/common/ring/test_builder.py
+++ b/test/unit/common/ring/test_builder.py
@@ -73,6 +73,11 @@ class TestRingBuilder(unittest.TestCase):
         self.assertFalse(rb.devs_changed)
         self.assertEqual(rb.version, 0)
         self.assertIsNotNone(rb._last_part_moves)
+        rd = rb.get_ring()
+        self.assertEqual(rd.devs, [])
+        self.assertEqual(rd.version, 0)
+        self.assertIsNone(rd.next_part_power)
+        self.assertEqual(rd.replica_count, 0)
 
     def test_overlarge_part_powers(self):
         expected_msg = 'part_power must be at most 32 (was 33)'