diff --git a/src/testdir/test_timers.vim b/src/testdir/test_timers.vim
index 70a41e9..152f725 100644
--- a/src/testdir/test_timers.vim
+++ b/src/testdir/test_timers.vim
@@ -20,7 +20,7 @@
   let slept = WaitFor('g:val == 1')
   call assert_equal(1, g:val)
   if has('reltime')
-    call assert_inrange(50, 100, slept)
+    call assert_inrange(49, 100, slept)
   else
     call assert_inrange(20, 100, slept)
   endif
@@ -32,7 +32,7 @@
   let slept = WaitFor('g:val == 3')
   call assert_equal(3, g:val)
   if has('reltime')
-    call assert_inrange(150, 250, slept)
+    call assert_inrange(149, 250, slept)
   else
     call assert_inrange(80, 200, slept)
   endif
@@ -57,7 +57,7 @@
   let slept = WaitFor('g:val == 1')
   call assert_equal(1, g:val)
   if has('reltime')
-    call assert_inrange(50, 130, slept)
+    call assert_inrange(49, 130, slept)
   else
     call assert_inrange(20, 100, slept)
   endif