diff --git a/contentcuration/contentcuration/models.py b/contentcuration/contentcuration/models.py
index ced4623e8f..fb01282eb0 100644
--- a/contentcuration/contentcuration/models.py
+++ b/contentcuration/contentcuration/models.py
@@ -468,11 +468,15 @@ def get_available_staged_space(self):
             .aggregate(size=Sum("file_size"))["size"]
             or 0
         )
-        return float(max(self.disk_space - space_used, 0))
+        return float(max(self.get_effective_disk_space() - space_used, 0))
 
     def get_available_space(self, active_files=None):
         return float(
-            max(self.disk_space - self.get_space_used(active_files=active_files), 0)
+            max(
+                self.get_effective_disk_space()
+                - self.get_space_used(active_files=active_files),
+                0,
+            )
         )
 
     def get_user_active_trees(self):
diff --git a/contentcuration/contentcuration/tests/test_user.py b/contentcuration/contentcuration/tests/test_user.py
index 585932aa9c..d7362a1a43 100644
--- a/contentcuration/contentcuration/tests/test_user.py
+++ b/contentcuration/contentcuration/tests/test_user.py
@@ -7,7 +7,9 @@
 import json
 import sys
 import tempfile
+import uuid
 
+from django.core.exceptions import PermissionDenied
 from django.core.management import call_command
 from django.test import TransactionTestCase
 from django.urls import reverse_lazy
@@ -269,3 +271,38 @@ def test_effective_disk_space_with_canceled_subscription(self):
             subscription_disk_space=50 * 1024 * 1024 * 1024,
         )
         self.assertEqual(self.user.get_effective_disk_space(), 500 * 1024 * 1024)
+
+    def test_available_space_includes_subscription(self):
+        UserSubscription.objects.create(
+            user=self.user,
+            stripe_subscription_status="active",
+            subscription_disk_space=50 * 1024 * 1024 * 1024,
+        )
+        self.assertEqual(
+            self.user.get_available_space(),
+            float(500 * 1024 * 1024 + 50 * 1024 * 1024 * 1024),
+        )
+
+    def test_check_space_allows_upload_within_subscription(self):
+        UserSubscription.objects.create(
+            user=self.user,
+            stripe_subscription_status="active",
+            subscription_disk_space=50 * 1024 * 1024 * 1024,
+        )
+        try:
+            self.user.check_space(1024 * 1024 * 1024, uuid.uuid4().hex)
+        except PermissionDenied:
+            self.fail("Subscription space was not counted towards the upload quota")
+
+    def test_check_space_rejects_upload_beyond_subscription(self):
+        UserSubscription.objects.create(
+            user=self.user,
+            stripe_subscription_status="active",
+            subscription_disk_space=50 * 1024 * 1024 * 1024,
+        )
+        with self.assertRaises(PermissionDenied):
+            self.user.check_space(51 * 1024 * 1024 * 1024, uuid.uuid4().hex)
+
+    def test_check_space_rejects_upload_without_subscription(self):
+        with self.assertRaises(PermissionDenied):
+            self.user.check_space(1024 * 1024 * 1024, uuid.uuid4().hex)