diff --git a/litellm/litellm_core_utils/duration_parser.py b/litellm/litellm_core_utils/duration_parser.py
index 39cd14b2b4e..d93639b1f4f 100644
--- a/litellm/litellm_core_utils/duration_parser.py
+++ b/litellm/litellm_core_utils/duration_parser.py
@@ -363,4 +363,4 @@ def _handle_month_reset(current_time: datetime, base_midnight: datetime, value:
         second=0,
         microsecond=0,
         tzinfo=current_time.tzinfo,
-    )
\ No newline at end of file
+    )
diff --git a/tests/test_duration_parser.py b/tests/test_duration_parser.py
new file mode 100644
index 00000000000..9f780c1c3f6
--- /dev/null
+++ b/tests/test_duration_parser.py
@@ -0,0 +1,12 @@
+import pytest
+from litellm.litellm_core_utils.duration_parser import duration_in_seconds
+
+def test_unlimited_budget_duration():
+    # 1. Test that the bug is fixed (Empty/None values safely return None)
+    assert duration_in_seconds("None") is None
+    assert duration_in_seconds("null") is None
+    assert duration_in_seconds("") is None
+    assert duration_in_seconds(None) is None
+
+    # 2. Test that normal math still works (30 days = 2,592,000 seconds)
+    assert duration_in_seconds("30d") == 2592000
\ No newline at end of file