diff --git a/reporting/markslider b/reporting/markslider
index 7741a23..ffd44c1 100755
--- a/reporting/markslider
+++ b/reporting/markslider
@@ -98,7 +98,8 @@ while true
 do 
     # print slide $i
     NO_SLIDES=$( grep -ce "^# " "$1" )
-    COLS=$(( $( tput cols ) - 3 ))
+    SLIDE_CHARS=$(( ${#i} + ${#NO_SLIDES} +1 ))
+    COLS=$(( $( tput cols ) - $SLIDE_CHARS ))
     [ "$cmd" = "e" ] && read -N 1 foo
     display_slide "$1" $i
     # save cursor location