diff --git a/vlfi.el b/vlfi.el
index 531511f..7462093 100644
--- a/vlfi.el
+++ b/vlfi.el
@@ -87,10 +87,13 @@ with the prefix argument DECREASE it is halved."
 
 (defun vlfi-format-buffer-name ()
   "Return format for vlfi buffer name."
-  (format "%s(%s)[%d,%d](%d)"
-          (file-name-nondirectory buffer-file-name)
-          (file-size-human-readable vlfi-file-size)
-          vlfi-start-pos vlfi-end-pos vlfi-batch-size))
+  (let ((vlfi-file-size-float (float vlfi-file-size)))
+    (format "%s(%s)[%.2f-%.2f%%%%](%d)"
+            (file-name-nondirectory buffer-file-name)
+            (file-size-human-readable vlfi-file-size)
+            (* 100 (/ vlfi-start-pos vlfi-file-size-float))
+            (* 100 (/ vlfi-end-pos vlfi-file-size-float))
+            vlfi-batch-size)))
 
 (defun vlfi-update-buffer-name ()
   "Update the current buffer name."