diff --git a/litellm/cost_calculator.py b/litellm/cost_calculator.py
index 65c09940b04..2502bfbfbdc 100644
--- a/litellm/cost_calculator.py
+++ b/litellm/cost_calculator.py
@@ -190,9 +190,10 @@ def _cost_per_token_custom_pricing_helper(
         )
         if cache_read_input_token_cost is not None:
             if not cache_read_input_tokens and usage_object is not None:
-                cache_read_input_tokens = _parse_prompt_tokens_details(usage_object)[
-                    "cache_hit_tokens"
-                ]
+                cache_read_input_tokens = (
+                    getattr(usage_object, "cache_read_input_tokens", None)
+                    or _parse_prompt_tokens_details(usage_object)["cache_hit_tokens"]
+                )
             cache_read_tokens = max(0, cache_read_input_tokens or 0)
             uncached_prompt_tokens = max(0, prompt_tokens - cache_read_tokens)
             input_cost = (
diff --git a/tests/test_litellm/test_cost_calculator.py b/tests/test_litellm/test_cost_calculator.py
index 02881e2af1b..435785243f1 100644
--- a/tests/test_litellm/test_cost_calculator.py
+++ b/tests/test_litellm/test_cost_calculator.py
@@ -81,6 +81,36 @@ def test_completion_cost_custom_pricing_uses_cache_read_rate():
     assert cost == pytest.approx(0.011684)
 
 
+def test_completion_cost_custom_pricing_uses_top_level_cache_read_tokens():
+    usage = Usage(
+        prompt_tokens=100,
+        completion_tokens=10,
+        total_tokens=110,
+        cache_read_input_tokens=80,
+    )
+    response = ModelResponse(
+        id="test-id",
+        created=1234567890,
+        model="anthropic/claude-sonnet-4",
+        object="chat.completion",
+        choices=[],
+        usage=usage,
+    )
+
+    cost = completion_cost(
+        completion_response=response,
+        model="anthropic/claude-sonnet-4",
+        custom_llm_provider="anthropic",
+        custom_cost_per_token={
+            "input_cost_per_token": 1.0,
+            "output_cost_per_token": 2.0,
+            "cache_read_input_token_cost": 0.25,
+        },
+    )
+
+    assert cost == pytest.approx(60.0)
+
+
 def test_completion_cost_custom_pricing_without_cache_read_rate_preserves_input_rate():
     usage = Usage(
         prompt_tokens=6074,