diff --git a/Signal/src/ViewControllers/DebugUI/DebugUIBackup.m b/Signal/src/ViewControllers/DebugUI/DebugUIBackup.m
index f1d57eb2d..ab13077e6 100644
--- a/Signal/src/ViewControllers/DebugUI/DebugUIBackup.m
+++ b/Signal/src/ViewControllers/DebugUI/DebugUIBackup.m
@@ -134,7 +134,8 @@ NS_ASSUME_NONNULL_BEGIN
                                                   NSData *_Nullable data =
                                                       [NSKeyedArchiver archivedDataWithRootObject:interaction];
                                                   OWSAssertDebug(data);
-                                                  interactionSizeTotal += data.length;
+                                                  ows_add_overflow(
+                                                      interactionSizeTotal, data.length, &interactionSizeTotal);
                                               }];
         [transaction enumerateKeysAndObjectsInCollection:[TSAttachment collection]
                                               usingBlock:^(NSString *key, id object, BOOL *stop) {
@@ -143,7 +144,8 @@ NS_ASSUME_NONNULL_BEGIN
                                                   NSData *_Nullable data =
                                                       [NSKeyedArchiver archivedDataWithRootObject:attachment];
                                                   OWSAssertDebug(data);
-                                                  attachmentSizeTotal += data.length;
+                                                  ows_add_overflow(
+                                                      attachmentSizeTotal, data.length, &attachmentSizeTotal);
                                               }];
     }];
 
diff --git a/Signal/src/util/OWSBackupExportJob.m b/Signal/src/util/OWSBackupExportJob.m
index a541e1072..778851429 100644
--- a/Signal/src/util/OWSBackupExportJob.m
+++ b/Signal/src/util/OWSBackupExportJob.m
@@ -630,27 +630,30 @@ NS_ASSUME_NONNULL_BEGIN
     {
         unsigned long long databaseFileSize = 0;
         for (OWSBackupExportItem *item in self.unsavedDatabaseItems) {
-            databaseFileSize += [OWSFileSystem fileSizeOfPath:item.encryptedItem.filePath].unsignedLongLongValue;
+            unsigned long long fileSize =
+                [OWSFileSystem fileSizeOfPath:item.encryptedItem.filePath].unsignedLongLongValue;
+            ows_add_overflow(databaseFileSize, fileSize, &databaseFileSize);
         }
         OWSLogInfo(@"exporting %@: count: %zd, bytes: %llu.",
             @"database items",
             self.unsavedDatabaseItems.count,
             databaseFileSize);
-        totalFileSize += databaseFileSize;
-        totalFileCount += self.unsavedDatabaseItems.count;
+        ows_add_overflow(totalFileSize, databaseFileSize, &totalFileSize);
+        ows_add_overflow(totalFileCount, self.unsavedDatabaseItems.count, &totalFileCount);
     }
     {
         unsigned long long attachmentFileSize = 0;
         for (OWSAttachmentExport *attachmentExport in self.unsavedAttachmentExports) {
-            attachmentFileSize +=
+            unsigned long long fileSize =
                 [OWSFileSystem fileSizeOfPath:attachmentExport.attachmentFilePath].unsignedLongLongValue;
+            ows_add_overflow(attachmentFileSize, fileSize, &attachmentFileSize);
         }
         OWSLogInfo(@"exporting %@: count: %zd, bytes: %llu.",
             @"attachment items",
             self.unsavedAttachmentExports.count,
             attachmentFileSize);
-        totalFileSize += attachmentFileSize;
-        totalFileCount += self.unsavedAttachmentExports.count;
+        ows_add_overflow(totalFileSize, attachmentFileSize, &totalFileSize);
+        ows_add_overflow(totalFileCount, self.unsavedAttachmentExports.count, &totalFileSize);
     }
     OWSLogInfo(@"exporting %@: count: %zd, bytes: %llu.", @"all items", totalFileCount, totalFileSize);