diff --git a/src/widgets/proxmoxbackupserver/component.jsx b/src/widgets/proxmoxbackupserver/component.jsx
index d6320d61..45550aee 100644
--- a/src/widgets/proxmoxbackupserver/component.jsx
+++ b/src/widgets/proxmoxbackupserver/component.jsx
@@ -29,7 +29,15 @@ export default function Component({ service }) {
     );
   }
 
-  const datastoreUsage = datastoreData.data ? (datastoreData.data[0].used / datastoreData.data[0].total) * 100 : 0;
+  // check for presence of datastore key
+  const hasDatastore = !!widget.datastore;
+  // return index of specified datastore
+  const datastoreIndex = hasDatastore ? datastoreData.data.findIndex(function(ds) { return ds.store == widget.datastore }) : -1;
+  // calculate usage for specified datastore, unless no match, then calculate for all datastores returned by API
+  const datastoreUsage = (datastoreIndex > -1) 
+  ? (datastoreData.data[datastoreIndex].used / datastoreData.data[datastoreIndex].total) * 100 
+  : ((datastoreData.data.reduce((sum, datastore) => sum + datastore.used, 0) / (datastoreData.data.reduce((sum, datastore) => sum + datastore.total, 0)))) * 100;
+  
   const cpuUsage = hostData.data.cpu * 100;
   const memoryUsage = (hostData.data.memory.used / hostData.data.memory.total) * 100;
   const failedTasks = tasksData.total >= 100 ? "99+" : tasksData.total;