diff --git a/ui/src/views/storage/CreateVolume.vue b/ui/src/views/storage/CreateVolume.vue
index 3efe31a34e2a..b8c5e307decf 100644
--- a/ui/src/views/storage/CreateVolume.vue
+++ b/ui/src/views/storage/CreateVolume.vue
@@ -269,6 +269,9 @@ export default {
           values.virtualmachineid = this.resource.id
           values.zoneid = this.resource.zoneid
         }
+        if (this.customDiskOffering) {
+          values.size = values.size.trim()
+        }
         if (this.createVolumeFromSnapshot) {
           values.snapshotid = this.resource.id
         }