diff --git a/comfy_extras/nodes_number_convert.py b/comfy_extras/nodes_number_convert.py
index a8ec44e47..b2822c856 100644
--- a/comfy_extras/nodes_number_convert.py
+++ b/comfy_extras/nodes_number_convert.py
@@ -6,6 +6,8 @@ inputs into FLOAT and INT outputs.
 
 from __future__ import annotations
 
+import math
+
 from typing_extensions import override
 
 from comfy_api.latest import ComfyExtension, io
@@ -53,12 +55,17 @@ class NumberConvertNode(io.ComfyNode):
             except ValueError:
                 raise ValueError(
                     f"Cannot convert string to number: {value!r}"
-                )
+                ) from None
         else:
             raise TypeError(
                 f"Unsupported input type: {type(value).__name__}"
             )
 
+        if not math.isfinite(float_val):
+            raise ValueError(
+                f"Cannot convert non-finite value to number: {float_val}"
+            )
+
         return io.NodeOutput(float_val, int(float_val))
 
 
diff --git a/tests-unit/comfy_extras_test/nodes_number_convert_test.py b/tests-unit/comfy_extras_test/nodes_number_convert_test.py
new file mode 100644
index 000000000..0046fa8f4
--- /dev/null
+++ b/tests-unit/comfy_extras_test/nodes_number_convert_test.py
@@ -0,0 +1,123 @@
+import pytest
+from unittest.mock import patch, MagicMock
+
+mock_nodes = MagicMock()
+mock_nodes.MAX_RESOLUTION = 16384
+mock_server = MagicMock()
+
+with patch.dict("sys.modules", {"nodes": mock_nodes, "server": mock_server}):
+    from comfy_extras.nodes_number_convert import NumberConvertNode
+
+
+class TestNumberConvertExecute:
+    @staticmethod
+    def _exec(value) -> object:
+        return NumberConvertNode.execute(value)
+
+    # --- INT input ---
+
+    def test_int_input(self):
+        result = self._exec(42)
+        assert result[0] == 42.0
+        assert result[1] == 42
+
+    def test_int_zero(self):
+        result = self._exec(0)
+        assert result[0] == 0.0
+        assert result[1] == 0
+
+    def test_int_negative(self):
+        result = self._exec(-7)
+        assert result[0] == -7.0
+        assert result[1] == -7
+
+    # --- FLOAT input ---
+
+    def test_float_input(self):
+        result = self._exec(3.14)
+        assert result[0] == 3.14
+        assert result[1] == 3
+
+    def test_float_truncation_toward_zero(self):
+        result = self._exec(-2.9)
+        assert result[0] == -2.9
+        assert result[1] == -2  # int() truncates toward zero, not floor
+
+    def test_float_output_type(self):
+        result = self._exec(5)
+        assert isinstance(result[0], float)
+
+    def test_int_output_type(self):
+        result = self._exec(5.7)
+        assert isinstance(result[1], int)
+
+    # --- BOOL input ---
+
+    def test_bool_true(self):
+        result = self._exec(True)
+        assert result[0] == 1.0
+        assert result[1] == 1
+
+    def test_bool_false(self):
+        result = self._exec(False)
+        assert result[0] == 0.0
+        assert result[1] == 0
+
+    # --- STRING input ---
+
+    def test_string_integer(self):
+        result = self._exec("42")
+        assert result[0] == 42.0
+        assert result[1] == 42
+
+    def test_string_float(self):
+        result = self._exec("3.14")
+        assert result[0] == 3.14
+        assert result[1] == 3
+
+    def test_string_negative(self):
+        result = self._exec("-5.5")
+        assert result[0] == -5.5
+        assert result[1] == -5
+
+    def test_string_with_whitespace(self):
+        result = self._exec("  7.0  ")
+        assert result[0] == 7.0
+        assert result[1] == 7
+
+    def test_string_scientific_notation(self):
+        result = self._exec("1e3")
+        assert result[0] == 1000.0
+        assert result[1] == 1000
+
+    # --- STRING error paths ---
+
+    def test_empty_string_raises(self):
+        with pytest.raises(ValueError, match="Cannot convert empty string"):
+            self._exec("")
+
+    def test_whitespace_only_string_raises(self):
+        with pytest.raises(ValueError, match="Cannot convert empty string"):
+            self._exec("   ")
+
+    def test_non_numeric_string_raises(self):
+        with pytest.raises(ValueError, match="Cannot convert string to number"):
+            self._exec("abc")
+
+    def test_string_inf_raises(self):
+        with pytest.raises(ValueError, match="non-finite"):
+            self._exec("inf")
+
+    def test_string_nan_raises(self):
+        with pytest.raises(ValueError, match="non-finite"):
+            self._exec("nan")
+
+    def test_string_negative_inf_raises(self):
+        with pytest.raises(ValueError, match="non-finite"):
+            self._exec("-inf")
+
+    # --- Unsupported type ---
+
+    def test_unsupported_type_raises(self):
+        with pytest.raises(TypeError, match="Unsupported input type"):
+            self._exec([1, 2, 3])