diff --git a/InvenTree/InvenTree/conversion.py b/InvenTree/InvenTree/conversion.py
index c69bd73c0c..dc7c4a3224 100644
--- a/InvenTree/InvenTree/conversion.py
+++ b/InvenTree/InvenTree/conversion.py
@@ -134,12 +134,15 @@ def convert_physical_value(value: str, unit: str = None, strip_units=True):
     # If the value is specified strangely (e.g. as a fraction or a dozen), this can cause issues
     # So, we ensure that it is converted to a floating point value
     # If we wish to return a "raw" value, some trickery is required
-    if unit:
-        magnitude = ureg.Quantity(value.to(ureg.Unit(unit))).magnitude
-    else:
-        magnitude = ureg.Quantity(value.to_base_units()).magnitude
+    try:
+        if unit:
+            magnitude = ureg.Quantity(value.to(ureg.Unit(unit))).magnitude
+        else:
+            magnitude = ureg.Quantity(value.to_base_units()).magnitude
 
-    magnitude = float(ureg.Quantity(magnitude).to_base_units().magnitude)
+        magnitude = float(ureg.Quantity(magnitude).to_base_units().magnitude)
+    except Exception as exc:
+        raise ValidationError(_(f'Invalid quantity supplied ({exc})'))
 
     if strip_units:
         return magnitude
diff --git a/InvenTree/InvenTree/tests.py b/InvenTree/InvenTree/tests.py
index cbb8bf58d1..02d8b9c408 100644
--- a/InvenTree/InvenTree/tests.py
+++ b/InvenTree/InvenTree/tests.py
@@ -104,6 +104,21 @@ class ConversionTest(TestCase):
             q = InvenTree.conversion.convert_physical_value(val)
             self.assertAlmostEqual(q, expected, 3)
 
+    def test_invalid_units(self):
+        """Test conversion with bad units"""
+
+        tests = {
+            '3': '10',
+            '13': '-?-',
+            '-3': 'xyz',
+            '-12': '-12',
+            '1/0': '1/0',
+        }
+
+        for val, unit in tests.items():
+            with self.assertRaises(ValidationError):
+                InvenTree.conversion.convert_physical_value(val, unit)
+
     def test_invalid_values(self):
         """Test conversion of invalid inputs"""