diff --git a/test/manual/cedet/cedet-utests.el b/test/manual/cedet/cedet-utests.el
index d68b5b8c090..af6b4defb3c 100644
--- a/test/manual/cedet/cedet-utests.el
+++ b/test/manual/cedet/cedet-utests.el
@@ -252,9 +252,7 @@ Optional argument TITLE is the title of this testing session."
 (defun cedet-utest-elapsed-time (start end)
   "Copied from elp.el.  Was elp-elapsed-time.
 Argument START and END bound the time being calculated."
-  (+ (* (- (car end) (car start)) 65536.0)
-     (- (car (cdr end)) (car (cdr start)))
-     (/ (- (car (cdr (cdr end))) (car (cdr (cdr start)))) 1000000.0)))
+  (float-time (time-subtract start end)))
 
 (defun cedet-utest-log-shutdown (title &optional _errorcondition)
   "Shut-down a larger test suite.