diff --git a/lib/services/billing_service.dart b/lib/services/billing_service.dart
index 0b5c99e84..c3615e214 100644
--- a/lib/services/billing_service.dart
+++ b/lib/services/billing_service.dart
@@ -117,7 +117,7 @@ class BillingService {
     }
   }
 
-  Future<double> fetchUsageInGBs() async {
+  Future<int> fetchUsage() async {
     try {
       final response = await _dio.get(
         _config.getHttpEndpoint() + "/billing/usage",
@@ -131,7 +131,7 @@ class BillingService {
           },
         ),
       );
-      return convertBytesToGBs(response.data["usage"]);
+      return response.data["usage"];
     } catch (e) {
       throw e;
     }
diff --git a/lib/ui/settings_page.dart b/lib/ui/settings_page.dart
index bd0929bf5..40193f835 100644
--- a/lib/ui/settings_page.dart
+++ b/lib/ui/settings_page.dart
@@ -14,6 +14,7 @@ import 'package:photos/services/billing_service.dart';
 import 'package:photos/ui/loading_widget.dart';
 import 'package:photos/ui/subscription_page.dart';
 import 'package:photos/ui/web_page.dart';
+import 'package:photos/utils/data_util.dart';
 import 'package:photos/utils/dialog_util.dart';
 import 'package:photos/utils/toast_util.dart';
 import 'package:share/share.dart';
@@ -160,10 +161,10 @@ class BackupSettingsWidgetState extends State<BackupSettingsWidget> {
   }
 
   void _getUsage() {
-    BillingService.instance.fetchUsageInGBs().then((usage) async {
+    BillingService.instance.fetchUsage().then((usage) async {
       if (mounted) {
         setState(() {
-          _usageInGBs = usage;
+          _usageInGBs = convertBytesToGBs(usage);
         });
       }
     });
diff --git a/lib/ui/subscription_page.dart b/lib/ui/subscription_page.dart
index 442c4cd8c..a6eacf365 100644
--- a/lib/ui/subscription_page.dart
+++ b/lib/ui/subscription_page.dart
@@ -13,6 +13,7 @@ import 'package:photos/models/billing_plan.dart';
 import 'package:photos/models/subscription.dart';
 import 'package:photos/services/billing_service.dart';
 import 'package:photos/ui/loading_widget.dart';
+import 'package:photos/utils/data_util.dart';
 import 'package:photos/utils/dialog_util.dart';
 import 'package:photos/utils/toast_util.dart';
 import 'package:progress_dialog/progress_dialog.dart';
@@ -31,11 +32,18 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
   Subscription _currentSubscription;
   StreamSubscription _purchaseUpdateSubscription;
   ProgressDialog _dialog;
+  Future<int> _usageFuture;
+  bool _hasActiveSubscription;
 
   @override
   void initState() {
     _billingService.setIsOnSubscriptionPage(true);
     _currentSubscription = _billingService.getSubscription();
+    _hasActiveSubscription =
+        _currentSubscription != null && _currentSubscription.isValid();
+    if (_hasActiveSubscription) {
+      _usageFuture = _billingService.fetchUsage();
+    }
 
     _dialog = createProgressDialog(context, "please wait...");
 
@@ -50,11 +58,9 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
                 purchase.verificationData.serverVerificationData);
             await InAppPurchaseConnection.instance.completePurchase(purchase);
             Bus.instance.fire(UserAuthenticatedEvent());
-            final isUpgrade = _currentSubscription != null &&
-                _currentSubscription.isValid() &&
+            final isUpgrade = _hasActiveSubscription &&
                 newSubscription.storage > _currentSubscription.storage;
-            final isDowngrade = _currentSubscription != null &&
-                _currentSubscription.isValid() &&
+            final isDowngrade = _hasActiveSubscription &&
                 newSubscription.storage < _currentSubscription.storage;
             String text = "your photos and videos will now be backed up";
             if (isUpgrade) {
@@ -123,9 +129,8 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
     final planWidgets = List<Widget>();
     for (final plan in plans) {
       final productID = Platform.isAndroid ? plan.androidID : plan.iosID;
-      final isActive = _currentSubscription != null &&
-          _currentSubscription.isValid() &&
-          _currentSubscription.productID == productID;
+      final isActive =
+          _hasActiveSubscription && _currentSubscription.productID == productID;
       planWidgets.add(
         Material(
           child: InkWell(
@@ -134,6 +139,15 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
                 return;
               }
               await _dialog.show();
+              if (_usageFuture != null) {
+                final usage = await _usageFuture;
+                if (usage > plan.storage) {
+                  await _dialog.hide();
+                  showErrorDialog(
+                      context, "sorry", "you cannot downgrade to this plan");
+                  return;
+                }
+              }
               final ProductDetailsResponse response =
                   await InAppPurchaseConnection.instance
                       .queryProductDetails([productID].toSet());
@@ -173,13 +187,14 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
       widgets.add(Container(
         height: 50,
         child: FutureBuilder(
-          future: _billingService.fetchUsageInGBs(),
+          future: _usageFuture,
           builder: (BuildContext context, AsyncSnapshot snapshot) {
             if (snapshot.hasData) {
               return Padding(
                 padding: const EdgeInsets.all(16.0),
-                child: Text(
-                    "current usage is " + snapshot.data.toString() + " GB"),
+                child: Text("current usage is " +
+                    convertBytesToGBs(snapshot.data).toString() +
+                    " GB"),
               );
             } else if (snapshot.hasError) {
               return Container();