diff --git a/gcloud-java-storage/src/main/java/com/google/cloud/storage/StorageImpl.java b/gcloud-java-storage/src/main/java/com/google/cloud/storage/StorageImpl.java
index f4769905d8bc..8a33f2bc4203 100644
--- a/gcloud-java-storage/src/main/java/com/google/cloud/storage/StorageImpl.java
+++ b/gcloud-java-storage/src/main/java/com/google/cloud/storage/StorageImpl.java
@@ -571,7 +571,7 @@ public URL signUrl(BlobInfo blobInfo, long duration, TimeUnit unit, SignUrlOptio
       path.append('/');
     }
     if (blobInfo.name().startsWith("/")) {
-      path.setLength(stBuilder.length() - 1);
+      path.setLength(path.length() - 1);
     }
     path.append(blobInfo.name());
     stBuilder.append(path);